| SM ISO690:2012|
FELEA, Viorel; PRODAN, Lilian; ŞTEFANEŢ, Eric; CONG, Phamthan; ZHERLITSYN, S.; TSURKAN, Vladimir. Ultrasound propagation and magnetization studies of HgCr2S4 in magnetic fields. In: Materials Science and Condensed Matter Physics. Editia a 8-a, 12-16 septembrie 2016, Chişinău. Chişinău: Institutul de Fizică Aplicată, 2016, p. 107. ISBN 978-9975-9787-1-2.
|Materials Science and Condensed Matter Physics
Editia a 8-a, 2016
Conferința "International Conference on Materials Science and Condensed Matter Physics" |
8-th Edition, Chişinău, Moldova, 12-16 septembrie 2016
We report on ultrasound propagation and magnetization studies of HgCr2S4 spinel, performed as a function of temperature in static magnetic fields up to 14 T. In figure 1 the relative change of the sound velocity and magnetization as a function of temperature are presented at different magnetic fields. Two clear anomalies are revealed which indicated consecutive phase transformations. The first anomaly corresponds to a change in the slope of the sound velocity which coincides with an abrupt change in the slope of the attenuation (at 0 T) at TFM ≈ 54 K which signals the onset of ferromagnetic correlations. The second anomaly represents a minimum in the sound velocity and a peak in the attenuation and is attributed to the antiferromagnetic (AF) transition near TN ≈ 23 K suggesting strong spin-lattice coupling. The similar anomalies at TN and TFM have been observed in the magnetization studies which revealed non-conventional magnetic behavior resembling metamagnetic properties. Accordingly, the calculated saturation magnetization MS = 5.83 μB, is in good agreement with the theoretical value of MS = 6 μB, expected for two Cr3+ions in the 3d3 state. From the Curie-Weiss fit to the susceptibility at high temperatures the effective magnetic moment peff = 3.78 μB, and the Curie-Weiss temperature ΘCW = +144 K have been calculated. The dominance of the FM interactions despite the AFM ground state of HgCr2S4 indicates strong bond frustration. With application of external magnetic field the ferromagnetic correlations are intensified and at the same time, the antiferromagnetic state established below TN is shifted to lower temperatures. It was found that non-monotonic behavior of the magnetization and sound velocity disappears in magnetic fields above 1T. With subsequent increase of the magnetic field, the ferromagnetic correlations dominate throughout the region of temperatures investigated. Acknowledgments: We acknowledge financial support from the Institutional project 15.817.02.06F and project for young researchers 15.819.02.01F