Magnetoelastic Effect in Perovskite Orthochromite HoCrO3

Abstract

It is well established that many material properties, such as multiferroicity, magnetoresistance, or magnetoelectricity, emerge from strong interactions of spins and lattice (phonons). An in-depth understanding of spin–phonon coupling is key to understanding these properties. We demonstrate strong spin–phonon coupling in HoCrO₃ using powder X-ray diffraction measurements. Our investigations confirm magnetoelastic effects below antiferromagnetic phase transition, T_N ≈ 142 K. The lattice parameters and unit cell volume decrease normally with temperature up to ~ T_N, but decrease anomalously below T_N. By fitting the background thermal expansion for a non-magnetic lattice using the Debye–Grüneisen equation, we determined the lattice strain  ΔV_M due to the magnetoelastic effects as a function of temperature. We have also established that the lattice strain due to the magnetoelastic effect in HoCrO₃ couples with the square of the ordered magnetic moment of the Cr³⁺ ion.