Spontaneous ferromagnetism and magnetoresistance hysteresis in Ge1-xSnx alloys

On the Paramagnetic-Like Susceptibility Peaks at Zero Magnetic Field in [Formula: see text] Single Crystals

A weakly temperature-dependent paramagnetic-like susceptibility peak at zero magnetic field is observed in [Formula: see text] with only marginal amount of ferromagnetic impurities. The ferromagnetic hysteresis loop and the magnetic moment splitting between zero-field-cooled and field-cooled processes indicate ferromagnetism in the samples. The paramagnetic-like susceptibility peak height is proportional to the remanent magnetic moment of hysteresis loops. High-resolution transmission electron microscope image supports that the observed ferromagnetic feature originates from lattice distortion. These results imply that the weakly temperature-dependent paramagnetic-like susceptibility peak originates from weak lattice distortion and/or superparamagnetism.

The Lattice Distortion-Induced Ferromagnetism in the Chemical-Bonded MoSe2/WSe2 at Room Temperature

Ferromagnetism to non-ferromagnetism transition is detected in a chemically bonded MoSe[Formula: see text]/WSe[Formula: see text] powder with different thermal annealing temperatures. All samples exhibit ferromagnetism and Raman redshift, except for the 1100 °C thermally annealed sample in which the MoSe[Formula: see text] and WSe[Formula: see text] are thermally dissociated and geometrically separated. The element analysis reveals no significant element ratio difference and detectable magnetic elements in all samples. These results support that, in contrast to the widely reported structure defect or transition element dopant, the observed ferromagnetism originates from the structure distortion due to the chemical bonding at the interface between MoSe[Formula: see text] and WSe[Formula: see text].

MXene/ZIF-67/PAN Nanofiber Film for Ultra-sensitive Pressure Sensors

Flexible pressure sensors may be used in electronic skin (e-skin), artificial intelligence devices, and disease diagnosis, which require a large response range and high sensitivity. An appropriate design of the structure of the active layer can help effectively solve this problem. Herein, we aim at developing a wearable pressure sensor using the MXene/ZIF-67/polyacrylonitrile (PAN) nanofiber film, fabricated by electrospinning technology. Owing to the rough structure and three-dimensional network architecture, the MXene/ZIF-67/PAN film-based device displays a broad working range (0-100 kPa), good sensitivity (62.8 kPa^-1), robust mechanical stability (over 10,000 cycles), and fast response/recovery time (10/8 ms). Moreover, the fabricated pressure sensors can be used to detect and differentiate between different body motion information, including elbow bending, finger movements, and wrist pulses. Overall, this design of a rough three-dimensional conductive network structure shows potential in the field of wearable electronics and medical devices.

The High Coercivity Field in Chemically Bonded WSe2/MoSe2 Powder

We studied the magnetic properties of WSe2/MoSe2 powder. The coercivity field reaches 2600 Oe at 5 K, 4233 Oe at 100 K and 1300 Oe at 300 K. These are the highest values reported for two-dimensional transition metal dichalcogenides. This study is different from the widely reported vacancy and zigzag structure-induced ferromagnetism studies. Importantly, a Raman peak red shift was observed, and that supports the chemical bonding at the interface between WSe2 and MoSe2. The large coercivity field originates from the chemical bonding-induced structural distortion at the interface between WSe2 and MoSe2.