Séminaire Mike ZHITOMIRSKY

Jeudi 7 mars 2024, 14h00, salle E4.13b

Mike ZHITOMIRSKY

IRIG, CEA, Grenoble

Magnetic frustration in octahedral lattices: emergent complexity in applied field

Geometrically frustrated magnets typically consist of either triangular or tetrahedral blocks of magnetic ions. A novel frustrated motif is provided by octahedral blocks. Magnetic ions form a corner-sharing network of octahedra in antiperovskites and Mn3X intermetallics, whereas edge-shared octahedra emerge for the J1-J2 spin model on a face-centered cubic (fcc) lattice for a special ratio of two exchanges J2/J1 = 0.5.  We illustrate an emergent complex behavior of octahedral antiferromagnets by studying the magnetization process of the classical J1-J2 fcc antiferromagnet. Up to eight different phases exist in magnetic field including two fractional magnetization plateaus at M/Msat = 1/3 and 2/3. An unusual twist in the quantum order-by-disorder effect due to magnon-magnon interactions is also found for the nearest-neighbor fcc antiferromagnet in zero field.

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