Antiferromagnetic Resonances of (CH3NH3)2MnCl4 in a Magnetic Field at Arbitrary Angle to the Easy Axis

Abstract

We have studied the magnetic excitations of (CH3NH3)2MnCl4 by means of millimeter wave resonance techniques for magnetic fields at various angles to the easy axis. Our results are compared with standard spin wave calculations for the antiferromagnetic resonance and the resonance in the spin flop regime. Surprisingly, we observe a splitting of the resonance lines which increases with increasing angle between the c-axis of the sample and the static magnetic field and which is not described by simple spin wave theory.