Current-Induced Magnetic Switching in an L1_(0) FePt Single Layer with Large Perpendicular Anisotropy Through Spin–Orbit Torque

In this study,current-induced partial magnetization-based switching was realized through the spin–orbit torque(SOT)in single-layer L1_(0) FePt with a perpendicular anisotropy(K_(u⊥))of 1.19×10^(7) erg·cm^(-3)(1 erg·cm^(-3)=0.1 J·m^(-3)),and its corresponding SOT efficiency(βDL)was 8×10^(-6) Oe·(A·cm^(-2))^(-1)(1 Oe=79.57747 A·m^(-1)),which is several times higher than that of the traditional Ta/CoFeB/MgO structure reported in past work.The SOT in the FePt films originated from the structural inversion asymmetry in the FePt films since the dislocations and defects were inhomogeneously distributed within the samples.Furthermore,the FePt grown on MgO with a granular structure had a larger effective SOT field and effi-ciency than that grown on SrTiO_(3)(STO)with a continuous structure.The SOT efficiency was found to be considerably dependent on not only the sputtering temperature-induced chemical ordering but also the lattice mismatch-induced evolution of the microstructure.Our findings can provide a useful means of efficiently electrically controlling a magnetic bit that is highly thermally stable via SOT.

Micromachined Infrared Thermopile Detector Based on a Suspended Film Structure

The micro-electromechanical system(MEMS)infrared thermopile is the core working device of modern information detection systems such as spectrometers,gas sensors,and remote temperature sensors.We presented two different structures of MEMS infrared thermopiles based on suspended film structures.They both deposited silicon nitride over the entire surface as a passivated absorber layer in place of a separate absorber zone,and the thermocouple strip was oriented in the same direction as the temperature gradient.The same MEMS preparation process was used and finally two different structures of the thermopile were characterized separately for testing to verify the impact of our design on the detector.The test results show that the circular and double-ended symmetrical thermopile detectors have responsivities of 27.932 V/W and 23.205 V/W,specific detectivities of 12.1×10^(7) cm·Hz^(1/2)·W^(-1) and 10.1×10^(7) cm·Hz^(1/2)·W^(-1),and response time of 26.2 ms and 27.06 ms,respectively.In addition,rectangular double-ended symmetric thermopile has a larger field of view than a circular thermopile detector,but is not as mechanically stable as a circular thermopile.

A 0.19 ppm/°C bandgap reference circuit with high-PSRR

A high-order curvature-compensated CMOS bandgap reference（BGR） topology with a low temperature coefficient（TC） over a wide temperature range and a high power supply reject ratio（PSRR） is presented.High-order correction is realized by incorporating a nonlinear current INL, which is generated by ？V_（GS） across resistor into current generated by a conventional first-order current-mode BGR circuit. In order to achieve a high PSRR over a broad frequency range, a voltage pre-regulating technique is applied. The circuit was implemented in CSMC 0.5 μm 600 V BCD process. The experimental results indicate that the proposed topology achieves TC of0.19 ppm/°C over the temperature range of 165 °C（-40 to 125 °C）, PSRR of-123 d B @ DC and-56 d B @ 100 k Hz. In addition, it achieves a line regulation performance of 0.017%/V in the supply range of 2.8–20 V.