The low-temperature heat capacity of some lanthanide zirconates

Lutique, S.; Javorský, P.; Konings, R.J.M.; Krupa, J.C.; Genderen, A.C.G. van; Miltenburg, J.C. van; Wastin, F.

doi:10.1016/j.jct.2004.03.017

Cited by 53 publications

(48 citation statements)

References 26 publications

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“…Recently, several theoretical studies [16][17][18] [24], and more recently Pr 2 Hf 2 O 7 [25] have shown that the Pr 3+ moment has a strong Ising character, described by a non-Kramers magnetic doublet. As in spin ice, no magnetic long-range ordering is observed down to dilution temperature, and magnetic specific heat shows a broad peak at about 2 K [21,22,[24][25][26][27], similar to what is observed in the classical spin ice Dy 2 Ti 2 O 7 .…”

Section: Introductionsupporting

confidence: 64%

Antiferroquadrupolar correlations in the quantum spin ice candidatePr2Zr2O7

et al. 2016

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(2016) Antiferroquadrupolar correlations in the quantum spin ice candidate Pr2Zr2O7. Physical Review B, 94 (16). 165153 Permanent WRAP URL: http://wrap.warwick.ac.uk/87826 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher statement: © 2016 American Physical Society A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. We present an experimental study of the quantum spin ice candidate pyrochlore compound Pr 2 Zr 2 O 7 by means of magnetization measurements, specific heat, and neutron scattering up to 12 T and down to 60 mK. When the field is applied along the [111] and [110] directions, k = 0 field-induced structures settle in. We find that the ordered moment rises slowly, even at very low temperature, in agreement with macroscopic magnetization. Interestingly, for H [110], the ordered moment appears on the so-called α chains only. The spin excitation spectrum is essentially inelastic and consists in a broad flat mode centered at about 0.4 meV with a magnetic structure factor which resembles the spin ice pattern. For H [110] (at least up to 2.5 T), we find that a well-defined mode forms from this broad response, whose energy increases with H , in the same way as the temperature of the specific-heat anomaly. We finally discuss these results in the light of mean field calculations and propose an interpretation where quadrupolar interactions play a major role, overcoming the magnetic exchange. In this picture, the spin ice pattern appears shifted up to finite energy because of those interactions. We then propose a range of acceptable parameters for Pr 2 Zr 2 O 7 that allow to reproduce several experimental features observed under field. With these parameters, the actual ground state of this material would be an antiferroquadrupolar liquid with spin-ice-like excitations.

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Section: Introductionsupporting

confidence: 64%

Antiferroquadrupolar correlations in the quantum spin ice candidatePr2Zr2O7

et al. 2016

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“…The solid and dashed curves correspond to the results of calculations based on the CF energies obtained in the present work and in Ref. [56], respectively.…”

Section: Crystal Field Parametersmentioning

confidence: 53%

Structural and magnetic investigations of single-crystalline neodymium zirconate pyrochloreNd2Zr2O7

et al. 2015

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(2015) Structural and magnetic investigations of single-crystalline neodymium zirconate pyrochlore Nd2Zr2O7. Physical Review B (Condensed Matter and Materials Physics), 91 (17). 174416. Permanent WRAP URL:http://wrap.warwick.ac.uk/87756 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. We report structural and magnetic properties studies of large high-quality single crystals of the frustrated magnet Nd 2 Zr 2 O 7 . Powder x-ray diffraction analysis confirms that Nd 2 Zr 2 O 7 adopts the pyrochlore structure. Room-temperature x-ray diffraction and time-of-flight neutron-scattering experiments show that the crystals are stoichiometric in composition with no measurable site disorder. The temperature dependence of the magnetic susceptibility shows no magnetic ordering at temperatures down to 0.5 K. Fits to the magnetic susceptibility data using a Curie-Weiss law reveal a ferromagnetic coupling between the Nd moments. Magnetization versus field measurements show a local Ising anisotropy along the 111 axes of the Nd 3+ ions in the ground state. Specific heat versus temperature measurements in zero applied magnetic field indicate the presence of a thermal anomaly below T ∼ 7 K, but no evidence of magnetic ordering is observed down to 0.5 K. The experimental temperature dependence of the single-crystal bulk dc susceptibility and isothermal magnetization are analyzed using crystal field theory and the crystal field parameters and exchange coupling constants determined. Publisher

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“…Compounds with a positive Curie-Weiss temperature θ CW indicative of ferromagnetic interactions, along with a strong Ising-like anisotropy, are, a priori, possible QSI candidates. In this Letter, we focus on Nd 2 Zr 2 O 7 , which falls into this class, as shown by magnetization [6][7][8] and CEF studies [8,9]. Nd 2 Zr 2 O 7 stands out as a fascinating system because of an additional interesting property.…”

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confidence: 99%

Fluctuations and All-In–All-Out Ordering in Dipole-OctupoleNd2Zr2O7

et al. 2015

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We present an experimental study of the pyrochlore coumpound Nd2Zr2O7 by means of neutron scattering and magnetization measurements down to 90 mK. The Nd 3+ magnetic moments exhibit a strong local 111 Ising anisotropy together with a dipolar-octupolar nature, different from the standard Kramers-doublet studied so far. We show that, despite the positive Curie-Weiss temperature, Nd2Zr2O7 undergoes a transition around 285 mK towards an all-in−all-out antiferromagnetic state. We establish the (H, T ) phase diagram in the three directions of the applied field and reveal a metamagnetic transition around 0.1 T. The strongly reduced ordered magnetic moment as well as the unexpected shape of the magnetization curves demonstrate that Nd2Zr2O7 is not a standard Ising antiferromagnet. We propose that the peculiar nature of the Nd doublet combined with competing interactions explain these findings.

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The low-temperature heat capacity of some lanthanide zirconates

Cited by 53 publications

References 26 publications

Antiferroquadrupolar correlations in the quantum spin ice candidatePr2Zr2O7

Antiferroquadrupolar correlations in the quantum spin ice candidatePr2Zr2O7

Structural and magnetic investigations of single-crystalline neodymium zirconate pyrochloreNd2Zr2O7

Fluctuations and All-In–All-Out Ordering in Dipole-OctupoleNd2Zr2O7

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