Far-Infrared Antiferromagnetic Resonance in Hexagonal YMnO3
- 1 March 1969
- journal article
- conference paper
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 40 (3) , 1234-1235
- https://doi.org/10.1063/1.1657606
Abstract
Hexagonal YMnO3 is an unusual compound. It is ferroelectric, and below 80°K is a triangular compensated antiferromagnet with all spins perpendicular to the polar c axis. The Mn is trivalent on a distorted D3h site. We have calculated the resonant modes of this triangular system. Two modes are degenerate in zero field and resonate at the geometric mean of χ−1 and the uniaxial anisotropy. We have observed these modes at v̄ = 43.0 cm−1 and at 2°K. Using this value and χ⊥ = 1.53×10−4 we find the uniaxial anisotropy is 3.2×107 erg/cm3. In this model the modes are split by H ∥ c with a geff close to the g of the Mn3+ ion. We observe a linear splitting with geff = 1.90±0.1 for H∥ to 54 kOe. Crystal field theory predicts g = 2.0 and a single ion anisotropy of order 107 erg/cm3 in agreement with our data. The temperature dependence of v̄ implies a T3.5±0.5 dependence for M (0) − M (T) in the range 0.2 <T/TN<0.5. The third resonant mode was not observed, presumably because the in‐plane anisotropy is small.This publication has 4 references indexed in Scilit:
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