Nonuniversal scaling of the magnetocaloric effect as an insight into spin-lattice interactions in manganites

Anders Smith, Kaspar Kirstein Nielsen, Henrique Neves Bez, Christian Bahl

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Abstract

We measure the magnetocaloric effect of the manganite series La0.67Ca0.33-xSrxMnO3 by determining the isothermal entropy change upon magnetization, using variable-field calorimetry. The results demonstrate that the field dependence of the magnetocaloric effect close to the critical temperature is not given uniquely by the critical exponents of the ferromagnetic-paramagnetic phase transition, i.e., the scaling is nonuniversal. A theoretical description based on the Bean-Rodbell model and taking into account compositional inhomogeneities is shown to be able to account for the observed field dependence. In this way the determination of the nonuniversal field dependence of the magnetocaloric effect close to a phase transition can be used as a method to gain insight into the strength of the spin-lattice interactions of magnetic materials. The approach is shown also to be applicable to first-order transitions.
Original languageEnglish
Article number054411
JournalPhysical Review B
Volume94
Issue number5
Number of pages5
ISSN2469-9950
DOIs
Publication statusPublished - 2016

Cite this

Smith, Anders ; Nielsen, Kaspar Kirstein ; Neves Bez, Henrique ; Bahl, Christian. / Nonuniversal scaling of the magnetocaloric effect as an insight into spin-lattice interactions in manganites. In: Physical Review B. 2016 ; Vol. 94, No. 5.
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abstract = "We measure the magnetocaloric effect of the manganite series La0.67Ca0.33-xSrxMnO3 by determining the isothermal entropy change upon magnetization, using variable-field calorimetry. The results demonstrate that the field dependence of the magnetocaloric effect close to the critical temperature is not given uniquely by the critical exponents of the ferromagnetic-paramagnetic phase transition, i.e., the scaling is nonuniversal. A theoretical description based on the Bean-Rodbell model and taking into account compositional inhomogeneities is shown to be able to account for the observed field dependence. In this way the determination of the nonuniversal field dependence of the magnetocaloric effect close to a phase transition can be used as a method to gain insight into the strength of the spin-lattice interactions of magnetic materials. The approach is shown also to be applicable to first-order transitions.",
author = "Anders Smith and Nielsen, {Kaspar Kirstein} and {Neves Bez}, Henrique and Christian Bahl",
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doi = "10.1103/PhysRevB.94.054411",
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Nonuniversal scaling of the magnetocaloric effect as an insight into spin-lattice interactions in manganites. / Smith, Anders; Nielsen, Kaspar Kirstein; Neves Bez, Henrique; Bahl, Christian.

In: Physical Review B, Vol. 94, No. 5, 054411, 2016.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Nonuniversal scaling of the magnetocaloric effect as an insight into spin-lattice interactions in manganites

AU - Smith, Anders

AU - Nielsen, Kaspar Kirstein

AU - Neves Bez, Henrique

AU - Bahl, Christian

PY - 2016

Y1 - 2016

N2 - We measure the magnetocaloric effect of the manganite series La0.67Ca0.33-xSrxMnO3 by determining the isothermal entropy change upon magnetization, using variable-field calorimetry. The results demonstrate that the field dependence of the magnetocaloric effect close to the critical temperature is not given uniquely by the critical exponents of the ferromagnetic-paramagnetic phase transition, i.e., the scaling is nonuniversal. A theoretical description based on the Bean-Rodbell model and taking into account compositional inhomogeneities is shown to be able to account for the observed field dependence. In this way the determination of the nonuniversal field dependence of the magnetocaloric effect close to a phase transition can be used as a method to gain insight into the strength of the spin-lattice interactions of magnetic materials. The approach is shown also to be applicable to first-order transitions.

AB - We measure the magnetocaloric effect of the manganite series La0.67Ca0.33-xSrxMnO3 by determining the isothermal entropy change upon magnetization, using variable-field calorimetry. The results demonstrate that the field dependence of the magnetocaloric effect close to the critical temperature is not given uniquely by the critical exponents of the ferromagnetic-paramagnetic phase transition, i.e., the scaling is nonuniversal. A theoretical description based on the Bean-Rodbell model and taking into account compositional inhomogeneities is shown to be able to account for the observed field dependence. In this way the determination of the nonuniversal field dependence of the magnetocaloric effect close to a phase transition can be used as a method to gain insight into the strength of the spin-lattice interactions of magnetic materials. The approach is shown also to be applicable to first-order transitions.

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DO - 10.1103/PhysRevB.94.054411

M3 - Journal article

VL - 94

JO - Physical Review B (Condensed Matter and Materials Physics)

JF - Physical Review B (Condensed Matter and Materials Physics)

SN - 1098-0121

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