Enhancement in magnetocaloric properties of holmium chromite by gadolinium substitution

Journal Article · Thu Jul 28 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4959253· OSTI ID:22597778

Yin, S. ^[1]

---

1. Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

HoCrO{sub 3}, Ho{sub 0.67}Gd{sub 0.33}CrO{sub 3}, and GdCrO{sub 3} bulk powder samples were prepared by citrate route. The phase purity and the structural properties of the samples were examined by x-ray diffraction and Raman spectroscopic measurements. The dc magnetization data revealed that the Cr{sup 3+} ordering temperatures (Néel temperature) for the HoCrO{sub 3}, Ho{sub 0.67}Gd{sub 0.33}CrO{sub 3}, and GdCrO{sub 3} samples are 140 K, 148 K, and 167 K, respectively, while the ac magnetization data revealed that the rare-earth (Ho) ordering occurs at ∼8 K for HoCrO{sub 3} and Ho{sub 0.67}Gd{sub 0.33}CrO{sub 3} samples. Temperature-induced magnetization reversal and spin reorientation were observed in GdCrO{sub 3} bulk sample, which depends on applied magnetic field and disappears at ∼1500 Oe and 500 Oe, respectively. By fitting the dc magnetic data with Curie-Weiss law, the effective magnetic moments were calculated to be 11.66 μ{sub B}, 10.23 μ{sub B}, and 9.90 μ{sub B} for the HoCrO{sub 3}, Ho{sub 0.67}Gd{sub 0.33}CrO{sub 3}, and GdCrO{sub 3} samples, respectively. The isothermal magnetization data showed that the magnetic behavior changed from canted antiferromagnetic in low temperature region (below Néel temperature) to paramagnetic at high temperature. It was found that Gd substitution considerably improves the magnetocaloric effect of HoCrO{sub 3}. Pure GdCrO{sub 3} bulk sample showed giant magnetocaloric entropy change (31.6 J/kg K at temperature ∼5 K and at ∼70 kOe), which is higher than that for polycrystalline RMnO{sub 3}, RCrO{sub 3}, and RFeO{sub 3} bulk powder samples. This renders GdCrO{sub 3} useful for potential applications in low-temperature magnetic refrigeration.

• OSTI ID: 22597778
• Journal Information: Journal of Applied Physics, Vol. 120, Issue 4; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANTIFERROMAGNETISM
CHROMITES
CHROMIUM IONS
CITRATES
CURIE-WEISS LAW
ENTROPY
GADOLINIUM
HOLMIUM
MAGNETIC FIELDS
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MAGNETIZATION
MANGANATES
PARAMAGNETISM
POLYCRYSTALS
POWDERS
REFRIGERATION
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0400-1000 K
X-RAY DIFFRACTION