New magnetic phases and the absence of superconductivity in doped Hematophanite, Pb₄Fe₃O₈Cl

We searched for new magnetic and superconductivity phases in the hematophanite system [1], Pb₄Fe₃O₈Cl, which has structural similarities to some cuprates [2]. To enhance the potential number of subphases we synthesized inhomogeneous samples via powder metallurgy and explored electron and hole doping of both Pb, with Ga and Bi, and Fe, with Mn and Co. We used magnetic field modulated microwave spectroscopy [3], as well as vibrating sample magnetometry, to identify magnetic phase transitions as a function of temperature. Crystallographic phase information is obtained via x-ray diffraction and Rietveld refinement. We observe that in both the Ga and Co doped systems we induce multiple magnetic phase transitions that correspond to various subphases present in our samples. Although many magnetic phases were created in these samples there is no indication of the presence of a new superconducting phase above 4 K.
1. R.C. Rouse, Am. Mineral. 56, 625 (1971).
2. A.C. Mclaughlin and J.P. Attfield, The Synthesis, Structure and Physical Properties of the Layered Ruthenocuprates RuSr₂GdCu₂O₈ and Pb₂Sr₂Cu₂RuO₈Cl (Springer, Berlin, Heidelberg, 2002).
3. J.G. Ramírez, A.C. Basaran, J. de la Venta, J. Pereiro, and I.K. Schuller, Rep. Prog. Phys. 77, 093902 (2014).