Temperature dependent electron paramagnetic resonance study on magnetoelectric YCrO₃

Abstract

We report temperature dependent electron paramagnetic resonance (EPR) studies on polycrystalline YCrO<sub>3</sub> samples at X-band (9.46 GHz) in the temperature range of 120 K to 298 K. The EPR spectra exhibit a single broad line across the whole temperature range, attributed to Cr<sup>3+</sup> ions. The variation of EPR spectra parameters (line width, integrated intensity, and g-factor) as a function of temperature was analyzed to understand the nature of spin-dynamics in the paramagnetic region of YCrO<sub>3</sub>. A peak in the g-factor suggests the presence of a new phase within the paramagnetic state at an intermediate point of temperature <i>T</i><sub>IP</sub> ~ 230 K, attributed to the onset of short range canted antiferromagnetic correlations in the material much above 140 K, Néel temperature (<i>T</i><sub>N</sub>) of YCrO<sub>3</sub>. The EPR intensity increases with a decrease in temperature up to <i>T</i><sub>N</sub> due to the renormalization of the magnetic moments arising from the appearance of canted antiferromagnetic correlations. Further, temperature dependent dielectric measurements also exhibit an anomaly at ~ 230 K suggesting the presence of magnetodielectric coupling in YCrO<sub>3</sub>, with a possibility towards a relatively high temperature magnetodielectric system.

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“…The anomaly observed at ∼ 230 K also appears in the temperature-dependent dielectric measurements (see Fig. 12(b)), indicating the presence of a magneto-dielectric coupling in YCrO 3 [185]. Furthermore, the study also implies the existence of Cr 4+ ions (see Fig.…”

“…Furthermore, the study also implies the existence of Cr 4+ ions (see Fig. 6(a)) and a possible spin-orbital coupling in YCrO 3 [185].…”

“…Mall et al studied the temperature-dependent loss tangent (tanδ) and real dielectric constant (ε ) of poly-crystalline YCrO 3 as shown in Figs. 12-14 [185]. Upon warming, there is a sudden increase in ε above T N , and an anomaly appears in ε (T ) curve around T IP ∼ 230 K, suggesting a new phase formed in the paramagnetic state probably due to an onset of short-range CAFM correlations.…”

“…The electron paramagnetic resonance was measured on high-quality poly-crystalline YCrO 3 samples in a temperature range from 120 to 298 K while warming the samples [185]. The spectra parameters consist of line width, integrated intensity, and g-factor.…”

“…Upon warming, there is a sudden increase in ε above T N , and an anomaly appears in ε (T ) curve around T IP ∼ 230 K, suggesting a new phase formed in the paramagnetic state probably due to an onset of short-range CAFM correlations. The observed dielectric anomaly around T IP may indicate a coupling between lattice and spin orders of degree mediated by magneto-dielectric correlations [185]. Mall et al performed a study of detailed temperature-and frequency-dependent dielectric behaviours of poly-crystalline YCrO 3 ceramics [172].…”