Crystal Structure, Physical Properties, and Electronic and Magnetic Structure of the Spin S=5/2 Zigzag Chain Compound Bi2Fe(SeO3)2OCl3

We report the synthesis and characterization of the new bismuth iron selenite oxochloride Bi2Fe(SeO3)(2)OCl3. The main feature of its crystal structure is the presence of a reasonably isolated set of spin S = 5/2 zigzag chains of corner-sharing FeO6 octahedra decorated with BiO4Cl3, BiO3Cl3, and SeO3 groups. When the temperature is lowered, the magnetization passes through a broad maximum at T-max approximate to 130 K, which indicates the formation of a magnetic short-range correlation regime. The same behavior is demonstrated by the integral electron spin resonance intensity. The absorption is characterized by the isotropic effective factor g approximate to 2 typical for high-spin Fe3+ ions. The broadening of ESR absorption lines at low temperatures with the critical exponent beta = 7/4 is consistent with the divergence of the temperature-dependent correlation length expected for the quasi-one-dimensional antiferromagnetic spin chain upon approaching the long-range ordering transition from above. At T-N = 13 K, Bi2Fe(SeO3)(2)OCl3 exhibits a transition into an antiferromagnetically ordered state, evidenced in the magnetization, specific heat, and Mossbauer spectra. At T < T-N, the Fe-57 Mossbauer spectra reveal a low saturated value of the hyperfine field H-hf approximate to 44 T, which indicates a quantum spin reduction of spin-only magnetic moment Delta S/S approximate to 20%. The determination of exchange interaction parameters using first-principles calculations validates the quasi-one-dimensional nature of magnetism in this compound.