Controllable two- vs three-state magnetization switching in single-layer epitaxial Pd1-xFex films and epitaxial Pd0.92Fe0.08/Ag/Pd0.96Fe0.04 heterostructure

We have investigated the low-temperature magnetoresistive properties of a thin epitaxial Pd0.92Fe0.08 film at different directions of the current and the applied magnetic field. The obtained experimental results are well described within an assumption of a single-domain magnetic state of the film. In a wide range of the appled field directions, the magnetization reversal proceeds in two steps via the intermediate easy axis. An epitaxial heterostructure of two magnetically separated ferromagnetic layers, Pd0.92Fe0.08/Ag/Pd0.96Fe0.04, was synthesized and studied with the dc magnetometry. Its magnetic configuration diagram has been constructed and the conditions have been determined for a controllable switching between stable parallel, orthogonal, and antiparallel arrangements of magnetic moments of the layers.

Light helicity detector based on 2D magnetic semiconductor CrI3

Two-dimensional magnetic semiconductors provide a platform for studying physical phenomena at atomically thin limit, and promise magneto-optoelectronic devices application. Here, we report light helicity detectors based on graphene-CrI3-graphene vdW heterostructures. We investigate the circularly polarized light excited current and reflective magnetic circular dichroism (RMCD) under various magnetic fields in both monolayer and multilayer CrI3 devices. The devices exhibit clear helicity-selective photoresponse behavior determined by the magnetic state of CrI3. We also find abnormal negative photocurrents at higher bias in both monolayer and multilayer CrI3. A possible explanation is proposed for this phenomenon. Our work reveals the interplay between magnetic and optoelectronic properties in CrI3 and paves the way to developing spin-optoelectronic devices.

Investigations of the size distribution and magnetic properties of nanoparticles of Cu2OSeO3

Skyrmions in confined geometries have been a subject of increasing interest due to the different properties that they exhibit compared to their bulk counterparts. In this study, nanoparticles of skyrmion-hosting Cu2OSeO3 have been synthesised using a precipitation method followed by thermal treatment. This enables us to produce nanoparticles whose mean size varies from tens of nanometers to a few micrometers by varying the temperature and duration of the thermal decomposition of the precursor. These sizes span the ∼ 63 nm diameter of skyrmions in Cu2OSeO3, allowing investigations into how the magnetic state changes when the size of the geometrical confinement is similar to and smaller than the size of an isolated magnetic skyrmion. AC susceptibility measurements performed on nanoparticles with a size distribution from 15 to 250 nm show a change in the magnetic phase diagram compared to bulk Cu2OSeO3.

Skyrmion Formation in Nanodisks Using Magnetic Force Microscopy Tip

We demonstrated numerically the skyrmion formation in ultrathin nanodisks using a magnetic force microscopy tip. We found that the local magnetic field generated by the magnetic tip significantly affects the magnetization state of the nanodisks and leads to the formation of skyrmions. Experimentally, we confirmed the influence of the local field on the magnetization states of the disks. Micromagnetic simulations explain the evolution of the magnetic state during magnetic force microscopy scanning and confirm the possibility of skyrmion formation. The formation of the horseshoe magnetic domain is a key transition from random labyrinth domain states into the skyrmion state. We showed that the formation of skyrmions by the magnetic probe is a reliable and repetitive procedure. Our findings provide a simple solution for skyrmion formation in nanodisks.

Evolution of spin freezing transition and structural, magnetic phase diagram of Dy$$_{2-\textit{x}}$$La$$_\textit{x}$$Zr$$_{2}$$O$$_{7}$$ (0 $$\le$$ $$\textit{x}$$ $$\le$$ 2.0)

Dy$$_{2}$$ 2 Zr$$_{2}$$ 2 O$$_{7}$$ 7 a disordered pyrochlore system, exhibits the spin freezing behavior under the application of the magnetic field. We have performed detailed magnetic studies of Dy$$_{2-\textit{x}}$$ 2 - x La$$_\textit{x}$$ x Zr$$_{2}$$ 2 O$$_{7}$$ 7 to understand the evolution of the magnetic spin freezing in the system. Our studies suggest the stabilization of the pyrochlore phase with the substitution of non-magnetic La along with the biphasic mixture of fluorite and pyrochlore phases for the intermediate compositions. We observed that the spin freezing (T$$_{f}$$ f $$\sim$$ ∼ 17 K) at higher La compositions (1.5 $$\le$$ ≤ $$\textit{x}$$ x $$\le$$ ≤ 1.99) is similar to the field-induced spin freezing for low La compositions (0 $$\le$$ ≤ $$\textit{x}$$ x $$\le$$ ≤ 0.5) and the well-known spin ice systems Dy$$_{2}$$ 2 Ti$$_{2}$$ 2 O$$_{7}$$ 7 and Ho$$_{2}$$ 2 Ti$$_{2}$$ 2 O$$_{7}$$ 7 . The low-temperature magnetic state for higher La compositions (1.5 $$\le$$ ≤ $$\textit{x}$$ x $$\le$$ ≤ 1.99) culminates into a spin-glass like state below 6 K. Cole–Cole plot and Casimir-du Pr$$\acute{e}$$ e ´ fit shows the narrow distribution of spin relaxation time in these compounds.