Magnetic anisotropy of carbonate minerals at room temperature and 77 K

摘要: The relationship between magnetic properties and chemical composition of 19 natural carbonate single crystals the calcite, aragonite, dolomite groups azurite were investigated. Magnetic susceptibility was determined in low fields, anisotropy measured at room temperature 77 K using a high-field torque magnetometer. analyzed LA-ICP MS. Planar arrangement CO 3 -groups generates an oblate diamagnetic with minimum k along crystallographic c -axis all investigated anhydrous minerals. A prolate paramagnetic maximum 1 is produced by Fe 2+ trigonal lattice, which can lead to transition from shape total anisotropy. occurs calcite structure above concentration 400 ppm 150 K. difference − for pure 4.06 × 10 −10 m /kg increases 9.4 −9 800 Fe. In hexagonal aragonite structure, no due detected. Azurite shows strong = 1.5 −8 /kg, assigned Cu . minerals group azurite, but not group. Upon cooling K, 13.3 times 500 100 000 lattice 7.2 siderite.