Temperature-dependence of the Hall coefficient of NdNiO3 thin filmsAdam J Hauser Evgeny Mikheev Nelson E Moreno Tyler A Cain Jinwoo Hwang Jack Y Zhang andSusanne Stemmer Citation Applied Physics Letters 103 182105 (2013) doi 10106314828557 View online httpdxdoiorg10106314828557 View Table of Contents httpscitationaiporgcontentaipjournalapl10318ver=pdfcov Published by the AIP Publishing Articles you may be interested in Correlation between stoichiometry strain and metal-insulator transitions of NdNiO3 films Appl Phys Lett 106 092104 (2015) 10106314914002 DC current induced metal-insulator transition in epitaxial Sm06Nd04NiO3LaAlO3 thin film AIP Advances 4 057102 (2014) 10106314874642 Anisotropic-strain-controlled metal-insulator transition in epitaxial NdNiO3 films grown on orthorhombic NdGaO3substrates Appl Phys Lett 103 172110 (2013) 10106314826678 Effect of structural and magnetic exchange coupling on the electronic transport of NdNiO3 films intercalated withLa07Sr03MnO3 thin layers Appl Phys Lett 103 032403 (2013) 10106314813490 Electric currents induced step-like resistive jumps and negative differential resistance in thin films ofNd07Sr03MnO3 J Appl Phys 111 07E131 (2012) 10106313675998

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1681314091 On Mon 09 Mar 2015 163246

Temperature-dependence of the Hall coefficient of NdNiO3 thin films

Adam J Hauser Evgeny Mikheev Nelson E Moreno Tyler A Cain Jinwoo HwangJack Y Zhang and Susanne StemmerMaterials Department University of California Santa Barbara California 93106-5050 USA

(Received 18 September 2013 accepted 17 October 2013 published online 31 October 2013)

The Hall coefficient of epitaxial NdNiO3 films is evaluated in a wide range of temperatures from the

metallic into the insulating phase It is shown that for temperatures for which metallic and insulating

regions co-exist the Hall coefficient must be corrected for the time-dependence in the longitudinal

resistance which is due to a slow evolution of metallic and insulating domains The positive Hall and

negative Seebeck coefficients respectively in the metallic phase are characteristic for two bands

participating in the transport The change in the sign of the Hall coefficient to negative values in the

insulating phase is consistent with the suppression of the contribution from the large hole-like Fermi

surface ie the formation of a (pseudo)gap due to charge ordering VC 2013 AIP Publishing LLC

[httpdxdoiorg10106314828557]

The rare earth nickelates (chemical formula RNiO3

where R is a trivalent rare earth ion) undergo a metal-to-insu-

lator transition (for R 6frac14La) upon cooling that has generated

significant interest for understanding charge and spin ordering

phenomena in correlated materials1 and for potential applica-

tion in novel switching devices2ndash5 NdNiO3 is a prototype

RNiO3 exhibiting a metal-to-insulator transition (MIT) at a

temperature (TMIT) of 200 K (in bulk)6 that is accompanied

by a lowering of the symmetry from orthorhombic to mono-

clinic charge ordering7ndash9 and a complex antiferromagnetic

state10ndash12 The MIT is first-order resulting in the co-existence

of metallic and insulating regions over a finite temperature

range and time-dependence of the transport coefficients

within the two-phase region1314 The Hall coefficient (RH) is

a useful tool for the study of changes in the electronic struc-

ture at the MIT Unusual non-monotonic features have been

reported recently in the temperature-dependence of RH of

RNiO3rsquos515 In this letter we discuss studies of the resistivity

RH and the Seebeck coefficient of NdNiO3 films We show

that for measurements at temperatures that lie within the phase

coexistence region RH must be corrected for the drift in

the resistivity over time We interpret the results for the

drift-corrected RH in terms of the current understanding of the

electronic states of NdNiO3

Epitaxial NdNiO3 films were grown on (001) LaAlO3

by rf magnetron sputtering at a substrate temperature of

700 C The total growth pressure of a 31 ArO2 mixture

was 300 mTorr and the rf power was 80 W yielding a

growth rate of 33 nmh High-resolution x-ray diffraction

(XRD) measurements (Phillips MRD XPert Thin Film

Diffractometer) and high-angle annular dark-field (HAADF)

scanning transmission electron microscopy (STEM) were

performed to confirm the epitaxial orientation relationships

In the following we index all reflections and planes using

pseudo-cubic unit cells for the NdNiO3 films and the rhom-

bohedral substrate respectively Films were patterned into

Hall bar structures (300 lm channel width) via contact li-

thography Ohmic contacts of Ni(20 nm)Au(300 nm) were

deposited by electron beam evaporation and device isolation

was achieved with a wet etch of 25 HCl in water

Measurements of the in-plane longitudinal resistivity (Rxx)

the Hall resistivity (Rxy) and the Seebeck coefficient (S) as a

function of temperature were performed using a Quantum

Design Physical Properties Measurement System (PPMS)

Seebeck coefficient measurements are reported in the metal-

lic phase only where the error is less than 1 [this uncer-

tainty rises sharply below TMIT due to the large change in

resistance with temperature and high resistivity of the insu-

lating phase respectively] Rxx was measured between 300 K

and 2 K upon cooling and heating Rxy and Rxx were meas-

ured simultaneously from 130 K to 20 K upon cooling from

room temperature and back upon heating from 10 K using a

magnetic field (B) sweeps between 69 T Time-dependent

measurements were carried out for up to several hours as

described below

Figure 1(a) shows an on-axis XRD pattern for a

165-nm-thick NdNiO3 film Thickness fringes suggest a

FIG 1 (a) On-axis XRD around the 002 reflection of a 165 nm NdNiO3

film grown on (001) LaAlO3 (b) Off-axis XRD of the same film at a tilt

angle of Wfrac14 45 showing 011 reflections of film and substrate The double

peak of the LaAlO3 substrate is due to twinning (c) Cross-section

HAADF-STEM image (d) Longitudinal resistivity of a 165 nm film as a

function of temperature measured upon cooling and heating respectively

0003-69512013103(18)1821054$3000 VC 2013 AIP Publishing LLC103 182105-1

APPLIED PHYSICS LETTERS 103 182105 (2013)

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1681314091 On Mon 09 Mar 2015 163246

smooth surface and agree with the film thickness measured

in STEM The out-of-plane film lattice spacing is 3836 A

larger than that of bulk NdNiO3 (pseudo-cubic lattice param-

eter 381 A (Ref 16)) due to the compressive in-plane

strain imposed by the LaAlO3 (pseudo-cubic lattice parame-

ter 379 A) Off-axis XRD (Wfrac14 45 with respect to the sur-

face normal) around the 011 reflection also shows thickness

fringes [Fig 1(b)] The film peak position corresponds to a

lattice spacing d011 of 2697 A and an in-plane lattice spacing

of 3792 A identical to that of the substrate The films are

therefore coherently strained to the substrate Figure 1(c)

shows a HAADF-STEM image viewed along [010] confirm-

ing epitaxial growth Figure 1(d) shows that the films exhibit

a MIT at 100 K with a hysteresis that has a width of

25 K TMIT is comparable to that of NdNiO3 thin films

reported in the literature317 but is lower than that of bulk

which typical for thin RNiO3 films

Figure 2(a) shows Rxx as a function of time at different

temperatures around the MIT Within the temperature range

of the hysteresis seen in Fig 1(d) significant time-dependence

is apparent in Rxx that persists to longer than 8ndash10 hr ie the

maximum observation period in this study Figure 2(b) shows

a measure of the magnitude of the drift as a function of tem-

perature (T) which correlates with the hysteresis in Rxx(T) and

is roughly proportional to the slope of Rxx(T) This time de-

pendence has been reported previously for both bulk and thin

film NdNiO31418 where it was described by a stretched

exponential It reflects the time scales associated with the for-

mation of metallic (heating above TMIT) or insulating phases

(cooling below TMIT) respectively A single simple exponen-

tial could not describe our data but both a stretched exponen-

tial decay or the sum of two exponential decay functions with

different time constants (103 and 104 s) provided an excel-

lent fit

In Hall measurements a small parasitic contribution due

to Rxx exists due to the finite contact lead widths This results

in a non-linear Rxy as a function of B as well as a vertical

offset in RxyethBTHORN These are commonly corrected with a verti-

cal offset and removal of the part that is symmetric about

Bfrac14 0 For a non-ferromagnetic material however RxyethBTHORNwill still trace back over itself closely upon reversal of B

Figure 2(c) shows the effect of the drift on consecutive

RxyethBTHORN traces recorded at 80 K ie within the hysteretic re-

gime (dashed lines) Here B was swept back and forth form

the two maximum fields for many hours Subtracting the

modeled longitudinal resistance Rxx and multiplying by a

scaling factor yields a time-corrected Hall measurement

[shown as solid lines in Fig 2(c)] that yields a RH similar to

the one that the uncorrected data is converging to We note

that averaging one or several sweeps even when recorded

over the large time interval of 6 h shown in Fig 2(c) does

not give correct values for RH due to the long time constants

involved19

Figures 3(a) and 3(b) show the resistivity and drift-

corrected RH as a function of temperature around the MIT

Like the longitudinal resistivity RH exhibits hysteretic

behavior between 50 and 120 K In the metallic region

RH is positive as previously reported for NdNiO3 (Refs 3

and 20) and other RNiO3rsquos2122 Transport in the metallic

RNiO3rsquos is generally understood to be determined by two

bands that cross the Fermi level giving rise to a small elec-

tron pocket and a large hole Fermi surface respectively23ndash26

The large hole Fermi surface dominates RH In contrast the

Seebeck coefficient shown in Fig 3(c) is negative

FIG 2 (a) Time-dependence of the longitudinal resistance at different tem-

peratures around TMIT Shown is the percentage change from the value meas-

ured 5 min after the temperature has stabilized upon cooling from room

temperature (filled symbols) and heating from 10 K (open symbols) respec-

tively (b) Amount of drift as defined in (a) after 5 h as a function of temper-

ature under cooling (blue filled circles) and heating (orange open triangles)

respectively (c) Raw Rxy data (dashed lines) as a function a magnetic field

measured over 6 h of continuous field sweeps from 9 to 9 T at Tfrac14 80 K

Also shown is the drift-corrected Rxy (solid line)

182105-2 Hauser et al Appl Phys Lett 103 182105 (2013)

This article is copyrighted as indicated in the article Reuse of AIP content is subject to the terms at httpscitationaiporgtermsconditions Downloaded to IP

1681314091 On Mon 09 Mar 2015 163246

consistent with previous reports for NdNiO3 and related

RNiO315222728 The difference in the signs of the two trans-

port coefficients confirms the two-band nature of the electri-

cal transport in metallic NdNiO3 Furthermore RH is nearly

temperature independent in the metallic region but becomes

temperature dependent below TMIT In the insulating regime

RH is negative and changes linearly with temperature Down

to the lowest temperatures RH does not show any unusual

non-monotonic behavior The sign change near TMIT is con-

sistent with a (pseudo)gap opening in the large hole Fermi

surface andor its gradual disappearance causing the hole

density to decrease with temperature This will cause the

electron pocket to dominate RH and result in the observed

temperature dependence The formation of a (pseudo)gap in

the insulating phase is consistent with charge ordering

which has been well-established both theoretically and

experimentally for the insulating phase of NdNiO37ndash101229

In summary we have shown that the correct evaluation

of the Hall effect of RNiO3 films that undergo a MIT

requires correcting for the drift of the longitudinal

resistance in the two-phase region We find a positive and

temperature-independent RH in the metallic region that is

dominated by the large hole Fermi surface despite the

presence of a small electron pocket RH becomes

temperature-dependent and negative below the MIT which

is consistent with the hole Fermi surface opening up a

(pseudo)gap causing a decrease in the hole concentration

and RH becoming dominated by residual electron carriers

The authors thank Leon Balents and Jim Allen for help-

ful discussions This work was supported in part by FAME

one of six centers of STARnet a Semiconductor Research

Corporation program sponsored by MARCO and DARPA

AJH acknowledges support through an Elings Prize

Fellowship of the California Nanosystems Institute at

University of California Santa Barbara The work made use

of central facilities of the UCSB MRL which is supported

by the MRSEC Program of the National Science Foundation

under Award No DMR-1121053 The work also made use

of the UCSB Nanofabrication Facility a part of the NSF-

funded NNIN network

1M L Medarde J Phys Condens Matter 9 1679 (1997)2J Son S Rajan S Stemmer and S J Allen J Appl Phys 110 084503

(2011)3R Scherwitzl P Zubko I G Lezama S Ono A F Morpurgo G

Catalan and J-M Triscone Adv Mater 22 5517 (2010)4S Asanuma P-H Xiang H Yamada H Sato I H Inoue H Akoh A

Sawa K Ueno H Shimotani H Yuan et al Appl Phys Lett 97

142110 (2010)5W L Lim E J Moon J W Freeland D J Meyers M Kareev J

Chakhalian and S Urazhdin Appl Phys Lett 101 143111 (2012)6J S Zhou J B Goodenough and B Dabrowski Phys Rev Lett 94

226602 (2005)7U Staub G I Meijer F Fauth R Allenspach J G Bednorz J

Karpinski S M Kazakov L Paolasini and F drsquoAcapito Phys Rev Lett

88 126402 (2002)8J L Garcıa-Mu~noz M A G Aranda J A Alonso and M J Martinez-

Lope Phys Rev B 79 134432 (2009)9I I Mazin D I Khomskii R Lengsdorf J A Alonso W G Marshall

R A Ibberson A Podlesnyak M J Martinez-Lope and M M Abd-

Elmeguid Phys Rev Lett 98 176406 (2007)10V Scagnoli U Staub A M Mulders M Janousch G I Meijer G

Hammerl J M Tonnerre and N Stojic Phys Rev B 73 100409(R)

(2006)11S Lee R Chen and L Balents Phys Rev Lett 106 016405 (2011)12B Lau and A J Millis Phys Rev Lett 110 126404 (2013)13D Kumar K P Rajeev J A Alonso and M J Martinez-Lope J Phys

Condes Matter 21 485402 (2009)14D Kumar K P Rajeev A K Kushwaha and R C Budhani J Appl

Phys 108 063503 (2010)15S D Ha R Jaramillo D M Silevitch F Schoofs K Kerman J D

Baniecki and S Ramanathan Phys Rev B 87 125150 (2013)16J L Garcıa-Mu~noz J Rodriguez-Carvajal P Lacorre and J B Torrance

Phys Rev B 46 4414 (1992)17G Catalan R M Bowman and J M Gregg J Appl Phys 87 606

(2000)18D Kumar K P Rajeev J A Alonso and M J Martinez-Lope Phys

Rev B 88 014410 (2013)19See supplementary material at httpdxdoiorg10106314828557 for

results of RH obtained by time-averaging plots of sweeps of Rxy as a func-

tion of B at different temperatures20J Son B Jalan A P Kajdos L Balents S J Allen and S Stemmer

Appl Phys Lett 99 192107 (2011)21S W Cheong H Y Hwang B Batlogg A S Cooper and P C Canfield

Physica B 194ndash196 1087 (1994)22J Son P Moetakef J M LeBeau D Ouellette L Balents S J Allen

and S Stemmer Appl Phys Lett 96 062114 (2010)23N Hamada J Phys Chem Solids 54 1157 (1993)

FIG 3 (a) Longitudinal resistivity q and drift-corrected RH as a function of

temperature (b) Same as (a) but within a narrower range of temperatures to

show the positive RH in the metallic region (c) Seebeck coefficient as a

function of temperature in the metallic phase Measurements upon cooling

(heating) are shown as circles (triangles)

182105-3 Hauser et al Appl Phys Lett 103 182105 (2013)

This article is copyrighted as indicated in the article Reuse of AIP content is subject to the terms at httpscitationaiporgtermsconditions Downloaded to IP

1681314091 On Mon 09 Mar 2015 163246

consistent with previous reports for NdNiO3 and related

RNiO315222728 The difference in the signs of the two trans-

port coefficients confirms the two-band nature of the electri-

cal transport in metallic NdNiO3 Furthermore RH is nearly

temperature independent in the metallic region but becomes

temperature dependent below TMIT In the insulating regime

RH is negative and changes linearly with temperature Down

to the lowest temperatures RH does not show any unusual

non-monotonic behavior The sign change near TMIT is con-

sistent with a (pseudo)gap opening in the large hole Fermi

surface andor its gradual disappearance causing the hole

density to decrease with temperature This will cause the

electron pocket to dominate RH and result in the observed

temperature dependence The formation of a (pseudo)gap in

the insulating phase is consistent with charge ordering

which has been well-established both theoretically and

experimentally for the insulating phase of NdNiO37ndash101229

In summary we have shown that the correct evaluation

of the Hall effect of RNiO3 films that undergo a MIT

requires correcting for the drift of the longitudinal

resistance in the two-phase region We find a positive and

temperature-independent RH in the metallic region that is

dominated by the large hole Fermi surface despite the

presence of a small electron pocket RH becomes

temperature-dependent and negative below the MIT which

is consistent with the hole Fermi surface opening up a

(pseudo)gap causing a decrease in the hole concentration

and RH becoming dominated by residual electron carriers

The authors thank Leon Balents and Jim Allen for help-

ful discussions This work was supported in part by FAME

one of six centers of STARnet a Semiconductor Research

Corporation program sponsored by MARCO and DARPA

AJH acknowledges support through an Elings Prize

Fellowship of the California Nanosystems Institute at

University of California Santa Barbara The work made use

of central facilities of the UCSB MRL which is supported

by the MRSEC Program of the National Science Foundation

under Award No DMR-1121053 The work also made use

of the UCSB Nanofabrication Facility a part of the NSF-

funded NNIN network

1M L Medarde J Phys Condens Matter 9 1679 (1997)2J Son S Rajan S Stemmer and S J Allen J Appl Phys 110 084503

(2011)3R Scherwitzl P Zubko I G Lezama S Ono A F Morpurgo G

Catalan and J-M Triscone Adv Mater 22 5517 (2010)4S Asanuma P-H Xiang H Yamada H Sato I H Inoue H Akoh A

Sawa K Ueno H Shimotani H Yuan et al Appl Phys Lett 97

142110 (2010)5W L Lim E J Moon J W Freeland D J Meyers M Kareev J

Chakhalian and S Urazhdin Appl Phys Lett 101 143111 (2012)6J S Zhou J B Goodenough and B Dabrowski Phys Rev Lett 94

226602 (2005)7U Staub G I Meijer F Fauth R Allenspach J G Bednorz J

Karpinski S M Kazakov L Paolasini and F drsquoAcapito Phys Rev Lett

88 126402 (2002)8J L Garcıa-Mu~noz M A G Aranda J A Alonso and M J Martinez-

Lope Phys Rev B 79 134432 (2009)9I I Mazin D I Khomskii R Lengsdorf J A Alonso W G Marshall

R A Ibberson A Podlesnyak M J Martinez-Lope and M M Abd-

Elmeguid Phys Rev Lett 98 176406 (2007)10V Scagnoli U Staub A M Mulders M Janousch G I Meijer G

Hammerl J M Tonnerre and N Stojic Phys Rev B 73 100409(R)

(2006)11S Lee R Chen and L Balents Phys Rev Lett 106 016405 (2011)12B Lau and A J Millis Phys Rev Lett 110 126404 (2013)13D Kumar K P Rajeev J A Alonso and M J Martinez-Lope J Phys

Condes Matter 21 485402 (2009)14D Kumar K P Rajeev A K Kushwaha and R C Budhani J Appl

Phys 108 063503 (2010)15S D Ha R Jaramillo D M Silevitch F Schoofs K Kerman J D

Baniecki and S Ramanathan Phys Rev B 87 125150 (2013)16J L Garcıa-Mu~noz J Rodriguez-Carvajal P Lacorre and J B Torrance

Phys Rev B 46 4414 (1992)17G Catalan R M Bowman and J M Gregg J Appl Phys 87 606

(2000)18D Kumar K P Rajeev J A Alonso and M J Martinez-Lope Phys

Rev B 88 014410 (2013)19See supplementary material at httpdxdoiorg10106314828557 for

results of RH obtained by time-averaging plots of sweeps of Rxy as a func-

tion of B at different temperatures20J Son B Jalan A P Kajdos L Balents S J Allen and S Stemmer

Appl Phys Lett 99 192107 (2011)21S W Cheong H Y Hwang B Batlogg A S Cooper and P C Canfield

Physica B 194ndash196 1087 (1994)22J Son P Moetakef J M LeBeau D Ouellette L Balents S J Allen

and S Stemmer Appl Phys Lett 96 062114 (2010)23N Hamada J Phys Chem Solids 54 1157 (1993)

FIG 3 (a) Longitudinal resistivity q and drift-corrected RH as a function of

temperature (b) Same as (a) but within a narrower range of temperatures to

show the positive RH in the metallic region (c) Seebeck coefficient as a

function of temperature in the metallic phase Measurements upon cooling

(heating) are shown as circles (triangles)

182105-3 Hauser et al Appl Phys Lett 103 182105 (2013)

This article is copyrighted as indicated in the article Reuse of AIP content is subject to the terms at httpscitationaiporgtermsconditions Downloaded to IP

1681314091 On Mon 09 Mar 2015 163246

24R Eguchi A Chainani M Taguchi M Matsunami Y Ishida K Horiba

Y Senba H Ohashi and S Shin Phys Rev B 79 115122 (2009)25S B Lee R Chen and L Balents Phys Rev B 84 165119 (2011)26H K Yoo S I Hyun L Moreschini Y J Chang D W Jeong C H

Sohn Y S Kim H-D Kim A Bostwick E Rotenberg et al e-print

arXiv13090710[cond-matstr-el]

27X Q Xu J L Peng Z Y Li H L Ju and R L Greene Phys Rev B

48 1112 (1993)28K P Rajeev G V Shivashankar and A K Raychaudhuri Solid State

Commun 79 591 (1991)29T Mizokawa D I Khomskii and G A Sawatzky Phys Rev B 61

11263 (2000)

182105-4 Hauser et al Appl Phys Lett 103 182105 (2013)

This article is copyrighted as indicated in the article Reuse of AIP content is subject to the terms at httpscitationaiporgtermsconditions Downloaded to IP

1681314091 On Mon 09 Mar 2015 163246