${\text{SnO}}_2$ nanoparticles doped with Fe of different concentrations were synthesized by a chemical coprecipitation method. After calcination at $600°\text{C}$, the samples were characterized using x-ray diffraction (XRD), transmission electron microscope (TEM), and superconducting quantum interference device magnetometer. XRD shows that the solubility of Fe in ${\text{SnO}}_2$ (${\text{Sn}}_{1-x}{\text{Fe}}_x{\text{O}}_2$: primary phase where Fe substitutes Sn in ${\text{SnO}}_2$ matrix) is less than 7.5% $\left(x<0.075\right)$ and ${\text{Fe}}_2{\text{O}}_3$ (hematite) or ${\left({\text{Fe}}_{1-y}{\text{Sn}}_y\right)}_2{\text{O}}_3$ (where Sn substitutes Fe in ${\text{Fe}}_2{\text{O}}_3$ matrix) is evolved as a secondary phase for $x\ge 0.075$ along with ${\text{Sn}}_{1-x}{\text{Fe}}_x{\text{O}}_2$ (primary phase). TEM shows that the particles are crystalline and of size in the nanometric regime $\left(10\pm 3\text{nm}\right)$. The $M\left(T\right)$ and $M\left(H\right)$ studies indicated an antiferromagnetic (AFM) interaction in 3% and 5% (atomic weight) Fe-doped ${\text{SnO}}_2$ nanoparticles. The observed AFM interaction can be explained by the bound magnetic polaron model for insulating diluted magnetic semiconductor systems. It is seen that the strength of AFM interaction reduces with increase in doping concentration. On the other hand, 7.5% Fe-doped ${\text{SnO}}_2$ nanoparticles show the ferromagnetic interaction, but the origin of the observed ferromagnetism is identified due to the presence of ${\left({\text{Fe}}_{1-y}{\text{Sn}}_y\right)}_2{\text{O}}_3$ as a secondary phase.

Coherent THz optical lattice and hybridized phonon–magnon modes are triggered by femtosecond laser pulses in the antiferromagnetic van der Waals semiconductor FePS₃. The laser‐driven lattice and spin dynamics are investigated in a bulk crystal as well as in a 380 nm‐thick exfoliated flake as a function of the excitation photon energy, sample temperature and applied magnetic field. The pump‐probe magneto‐optical measurements reveal that the amplitude of a coherent phonon mode oscillating at 3.2 THz decreases as the sample is heated up to the Néel temperature. This signal eventually vanishes as the phase transition to the paramagnetic phase occurs, thus revealing its connection to the long‐range magnetic order. In the presence of an external magnetic field, the optically triggered 3.2 THz phonon hybridizes with a magnon mode, which is utilized to excite the hybridized phonon–magnon mode optically. These findings open a pathway toward the optical control of coherent THz photo–magnonic dynamics in a van der Waals antiferromagnet, which can be scaled down to the 2D limit.

The significant inversion symmetry breaking specific to wurtzite semiconductors, and the associated spontaneous electrical polarization, lead to outstanding features such as high density of carriers at the GaN/(Al,Ga)N interface—exploited in high-power/high-frequency electronics—and piezoelectric capabilities serving for nanodrives, sensors and energy harvesting devices. Here we show that the multifunctionality of nitride semiconductors encompasses also a magnetoelectric effect allowing to control the magnetization by an electric field. We first demonstrate that doping of GaN by Mn results in a semi-insulating material apt to sustain electric fields as high as 5 MV cm⁻¹. Having such a material we find experimentally that the inverse piezoelectric effect controls the magnitude of the single-ion magnetic anisotropy specific to Mn³⁺ ions in GaN. The corresponding changes in the magnetization can be quantitatively described by a theory developed here.

We investigate the magnetic behavior of (Fe,Co) codoped ZnO both theoretically and experimentally. The electronic structure calculation for both bulk and cluster systems of codoped ZnO, within the framework of $\text{DFT}+U$, stabilizes in a ferrimagnetic configuration for nearest-neighbor position of the codopants. The exchange properties of the codoped system are dependent on the distance and concentration of the dopants. The theoretical calculations also reveal the importance of defect states in mediating the long-range magnetic order in such systems. Experimentally obtained magnetic properties for several ranges of doping suggest a competitive mixing of ferrimagnetic and ferromagnetic behaviors within the sample. The segregated phase for higher percentage of doping has also been identified.

Heterostructures consisting of alternating GaN/AlN epitaxial layers represent the building blocks of state-of-the-art devices employed for active cooling and energy-saving lightning. Insights into the heat conduction of these structures are essential in the perspective of improving the heat management for prospective applications. Here, the cross-plane (perpendicular to the sample's surface) thermal conductivity of GaN/AlN superlattices as a function of the layers' thickness is established by employing the $3\omega$ -method. Moreover, the role of interdiffusion at the interfaces in the phonon scattering is taken into account in the modeling and data treatment. It is found that the cross-plane thermal conductivity of the epitaxial heterostructures can be driven to values as low as 5.9 W/(m·K) comparable with those reported for amorphous films, thus opening wide perspectives for optimized heat management in III-nitride-based epitaxial multilayers.