Magnetooptical Study of Spin-Orientation Phase Transition in $NdF{e}_3(B{O}_3{)}_4$ Single Crystal

Abstract

The magnetic field dependences of birefringence in a $NdF{e}_3(B{O}_3{)}_4$ single crystal have been measured in the case where the direction of light propagation coincides with the trigonal crystal axis $C_3$ ($k\Vert C_3$), and the external magnetic field is oriented along the second-order axis $C_2$ ($H\Vert C_2$). In the temperature range, in which an incommensurate phase exists with the formation of a long-period antiferromagnetic helix, the strongly pronounced jumps in the field dependence of birefringence are revealed and identified as a firstorder spin-orientation phase transition. The phase transition was accompanied by a hysteresis in the field dependences of birefringence. The $H-T$ phase diagram for a $NdF{e}_3(B{O}_3{)}_4$ single crystal has been plotted in the case where the magnetic field is oriented along the crystal axis $C_2$ ($H\Vert C_2$).

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