Strongly correlated oxides and multiferroic systems

investigating new materials, to be able to explore further, and extract new fundamental information on the mechanisms bringing forth those properties.

The research

The order or disorder of the spin and orbital degrees of freedom of electrons in transition metal oxides is responsible for a wide variety of phenomena [1]. For example, the colossal magnetoresistance (CMR) effect observed in manganese oxide compounds with an ABO3 perovskite structure (e.g. (La,Sr) MnO3 or (Pr,Ca)MnO3) results of the complex spin-orbital coupled state of the manganese lattice [2]. In materials with complex orbital order and/or spin structures, an electric polarization may be induced, making the material (in a large sense) magnetoelectric multiferroic [3]. Such materials display magnetoelectric effects, permitting e.g. the control of the magnetization of a material by means of an electric field or reciprocally the control of its polarization by means of a magnetic field, and are thus very attractive for application in many devices [4]. There are however few spintronic magnetoresistive oxides or magnetoelectric multiferroics which can be used at room temperature.

We are thus investigating new materials, to be able to explore further, and extract new fundamental information on the mechanisms bringing forth those properties.

References

“Complexity in Strongly Correlated Systems”, E. Dagotto, Science 309, 257 (2005).
“Orbital Physics in Transition-Metal Oxides”, Y. Tokura and N. Nagaosa, Science 288, 462 (2000).
“Classifying multiferroics: Mechanisms and effects ”, D. Khomskii, Physics 2, 20 (2009).
"Advances in magnetoelectric multiferroics", N. Spaldin and R. Ramesh, Nature Materials 18, 203 (2019).

Publications

Concentration and Temperature Dependence of the Structural, Magnetic, and Dielectric Properties of La2Ni(Mn1-xRux)O6 Solid Solutions, P. Pramanik, S. A. Ivanov, D. I. Turkinc, G. V. Bazuev, D. C. Joshi, O. I. Gyrdasova, R. Mathieu, J. Alloys Compd. 968, 171885 (2023).

Partial cation ordering, relaxor ferroelectricity and ferrimagnetism in Pb(Fe1-xYbx)2/3W1/3O3 solid solutions, S. A. Ivanov, D. C. Joshi, A. A. Bush, D. Wang, B. Sanyal, O. Eriksson, P. Nordblad, R. Mathieu, J. Appl. Phys. 128, 134102 (2020).

Spin and dipole order in geometrically frustrated mixed-valence manganite Pb3Mn7O15, S. A. Ivanov, A. A. Bush, M. Hudl, A. I. Stash, G. André, R. Tellgren, V. M. Cherepanov, A. V. Stepanov, K. E. Kamentsev, Y. Tokunaga, Y. Taguchi, Y. Tokura, P. Nordblad, and R. Mathieu, J. Mater. Sci.: Mater. Electron. 27, 12562 (2016).

Enhancement of antiferromagnetic interaction and transition temperature in M3TeO6 systems (M = Mn, Co, Ni, Cu), R. Mathieu, S. A. Ivanov, P. Nordblad, and M. Weil, Eur. Phys. J. B 86, 361 (2013).

The nanoscale phase separation in hole-doped manganites, R. Mathieu and Y. Tokura, J. Phys. Soc. Jpn. 76, 124706 (2007).