Heat capacity and entropy of MnF2 from 10 to 300 °K. Evaluation of the contributions associated with magnetic ordering

Control of antiferromagnetic domain distribution via polarization-dependent optical annealing

The absence of net magnetization inside antiferromagnetic domains has made the control of their spatial distribution quite challenging. Here we experimentally demonstrate an optical method for controlling antiferromagnetic domain distributions in MnF₂. Reduced crystalline symmetry can couple an order parameter with non-conjugate external stimuli. In the case of MnF₂, time-reversal symmetry is macroscopically broken reflecting the different orientations of the two magnetic sublattices. Thus, it exhibits different absorption coefficients between two orthogonal linear polarizations below its antiferromagnetic transition temperature under an external magnetic field. Illumination with linearly polarized laser light under this condition selectively destructs the formation of a particular antiferromagnetic order via heating. As a result, the other antiferromagnetic order is favoured inside the laser spot, achieving spatially localized selection of an antiferromagnetic order. Applications to control of interface states at antiferromagnetic domain boundaries, exchange bias and control of spin currents are expected.

The control of magnetic domains in antiferromagnets is limited by the lack of a net magnetic moment which may be manipulated by external stimuli. Here, the authors present an optical method for switching such domain states in MnF₂ based on azimuth-dependent absorption of linearly polarized light.