论文标题
来自EPR测量的偶极 - 海森贝格磁铁LIGDF4的微观自旋哈密顿量
Microscopic spin Hamiltonian for a dipolar-Heisenberg magnet LiGdF4 from EPR measurements
论文作者
论文摘要
低温电子顺磁共振测量测量是在liy_ {1-x} gd_xf_4的单晶上执行的，弱x = 0.005，中度x = 0.05 GD离子浓度。实验光谱的建模使我们能够精确确定父型LIGDF4材料的自旋哈密顿量的显微镜参数，包括最近的邻居交换常数。通过比较在我们的静态磁化测量值中获得的LIGDF4获得的强烈各向异性居里 - 韦斯温度，进一步测试了所获得的参数。我们发现LIGDF4中的主磁相互作用之间存在良好的平衡，这可能导致隐藏的磁性挫败感，可能导致延迟的磁有序和在低温下增强的磁平衡效应。
Low-temperature electron paramagnetic resonance measurements are performed on single crystals of LiY_{1-x}Gd_xF_4 with weak x=0.005 and moderate x=0.05 concentration of Gd ions. Modeling of the experimental spectra allows us to precisely determine microscopic parameters of the spin Hamiltonian of the parent LiGdF4 material, including the nearest-neighbor exchange constant. The obtained parameters are further tested by comparing a strongly anisotropic Curie-Weiss temperature obtained for LiGdF4 in our static magnetization measurements with theoretically computed values. We find a fine balance between principal magnetic interactions in LiGdF4, which results in a hidden magnetic frustration presumably leading to a delayed magnetic ordering and an enhanced magnetocaloric effect at low temperatures.
