Magnetic Structure of Ba2CaCo2Si6O17 with Zigzag Spin Chains of Co2+ in High Spin-3/2 State

The magnetic properties and crystal chemistry of the novel Ba2CaCo2Si6O17 compound exhibiting one-dimensional zigzag chains of Co2+ ions (S = 3/2) are investigated using powder X-ray diffraction (PXRD), scanning lectron microscopy, energy dispersive-Xray spectroscopy, and temperature and field-dependent magnetic measurements. The refinement of PXRD data suggests a Cmcm space group in orthorhombic symmetry for Ba2CaCo2Si6O17 compound, consisting of a CoO4 tetrahedral network including 1-D zigzag Co2+ chains. Microstructural and elemental analysis substantiate the proper stoichiometry of the synthesized material. Magnetic measurements show paramagnetic characteristics at room temperature, followed by a transition from paramagnetic to antiferromagnetic (AFM) ordering near 17 K, superimposed with weak ferromagnetic ordering (WFM) characteristics. Magnetic hysteresis (M-H) at 5 K depicts a sigmoid curve with unsaturated magnetization even at high fields. The negative Weiss temperature value approximate to-98 K substantiates the strong antiferromagnetic exchange interaction with a frustration index of approximate to 5.76. The effective paramagnetic moment is 3.34 mu B, close to the spin-only value 3.87 mu B of Co2+ (S = 3/2). The competing and short-range FM-AFM interaction is observed because of the zigzag Co2+ chain in the compound. The onset of WFM is attributed to the zigzag magnetic chain-induced lattice and spin distortion in Ba2CaCo2Si6O17 compound.