Macroscopic magnetic characterization of 〖Mn〗_4 Fe〖Si〗_3 single crystalline

Shatha Nazzal Naji Nazzal
شذى نزال ناجي نزال
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Al-Quds University
In this work, the macroscopic magnetization study on a single crystal of Mn4 FeSi3 reveals a variety of the magnetic properties. Magnetization measurements were implemented on a pre-oriented single crystal using Vibrating sample magnetometry (VSM) option. Two different protocols (isofield and isothermal) were followed and showed comparable magnetic response, implying that the system is always in thermodynamic equilibrium. The field dependent magnetization was measured by applying a magnetic field (up to 8 T) along the three symmetry directions of the hexagonal system ([001], [100], [120]). The experimentally calculated paramagnetic moment is determined as ⁓ 4.3(1) 𝜇B. The sample exhibits an obvious anisotropic magnetic behavior in the low temperature ranges. In agreement with earlier studies, the compound undergoes a paramagnetic to antiferromagnetic transition around 95 K. This transition is detected along all measured field strengths and field directions. A transition between two distinct antiferromagnetic phases, which was reported in the literature based on measurements on polycrystalline samples, is visible around 65 K only if the field is applied in [001] direction. The present results hint to a temperature independent field-induced transition in the low temperature region < 80 K for a field between 5 and 6 T. This transition manifests itself differently when the field is applied in different directions. The results hint towards the predominance of antiferromagnetic interactions and indicate a preference of moments to align perpendicular to the [001] direction. In addition, ferromagnetic correlations of the c-component of the magnetic moments are observed which can be suppressed with increasing the applied field. The latter results, in addition to the drop in the magnetization which occurs in vicinity of 80 K requires a microscopic method to probe the magnetic structure in Mn4FeSi3.