Switching on superferromagnetism

Abstract

Recent results in electric field control of magnetism have paved the way for the design of new magnetic and spintronic devices with enhanced and novel functionalities and low power consumption. Among the diversity of reported magnetoelectric effects, the possibility of switching on and off long-range ferromagnetic ordering close to room temperature stands out. Its binary character opens up the avenue for its implementation in magnetoelectric data storage devices. Here we show the possibility to locally switch on superferromagnetism in a wedge-shaped polycrystalline FE thin film deposited on top of ferroelectric and ferroelastic BaTiO 3 substrate. A superparamagnetic to superferromagnetic transition is observed for confined regions for which a voltage applied to the ferroelectric substrate induces a sizable strain. We argue that electric field-induced changes of magnetic anisotropy lead to an increase of the critical temperature separating the two regimes so that superparamagnetic regions develop collective long-range superferromagnetic behaviour.

Imaging and Harnessing Percolation at the Metal–Insulator Transition of NdNiO3 Nanogaps

“…or insulating (I-phase) domains around the NNO nanogaps, the spatially-resolved and temperaturedependent X-PEEM was performed at the UE49 PGM beamline of the BESSY II in the Helmholtz-Zentrum Berlin 26,27 .…”

“…To image the local distribution of metallic (M phase) or insulating (I phase) domains around the NNO nanogaps, the spatially resolved and temperature-dependent X-PEEM was performed at the UE49 PGM beamline of BESSY II at the Helmholtz Zentrum Berlin. 27,28 ■ ASSOCIATED CONTENT * S Supporting Information…”

“…The two-point resistance of the NNO nanogaps was performed with a temperature sweeping rate of 2 K/min. To image the local distribution of metallic (M phase) or insulating (I phase) domains around the NNO nanogaps, the spatially resolved and temperature-dependent X-PEEM was performed at the UE49 PGM beamline of BESSY II at the Helmholtz Zentrum Berlin. , …”

Heat Generation in Magnetic Hyperthermia by Manganese Ferrite-Based Nanoparticles Arises from Néel Collective Magnetic Relaxation

“…In addition, there is no doubt that this is also very important for biomedical applications in diagnosis and therapy, where techniques such as magnetic particle spectroscopy (MPS), magnetic particle imaging (MPI), and magnetic nanoparticle hyperthermia (MNH) are playing a role. − In this work, we are particularly interested in addressing the importance of Néel-like collective magnetic relaxation to heat generation through MNH therapy. We are also convinced that the analysis presented here also helps to understand some interesting nanomagnetism phenomena, such as, for instance, superferromagnetism. − …”

Extraordinary Nonlinear Optical Interaction from Strained Nanostructures in van der Waals CuInP2S6

“…Local strain engineering in particular serves as an efficient and reliable strategy to tailor the lattice structure and anisotropic properties. − In addition, it can stimulate multiple essential optoelectronic and electrical properties like carrier mobility, band gap, piezoelectricity, induced magnetism, , phase transition, and excitonic effects . These essential properties have been widely implemented in several intermediary and practical applications including improved carrier distribution and transport in piezoelectric 2D materials, improved solar cell efficiencies, single photon emitters, − and strain related spintronic devices. , …”