The present study explores the systematic investigation of resistive switching response of magnetron sputtered MoS2 thin films sandwiched between a Ni-Mn-In ferromagnetic shape memory alloy (bottom) and copper (top) electrodes. The Cu/MoS2/Ni-Mn-In device exhibits stable and reproducible bipolar resistive switching behavior. The current-voltage (I-V) analysis suggests that the device shows ohmic conduction behavior in the low resistance state (LRS) while space charge limited conduction is the dominating conduction mechanism in the high resistance state (HRS). The compliance current vs reset current measurements were also performed which reveals that the power consumption of the device can be suppressed by decreasing the compliance current. To explain the resistive switching behavior in the Cu/MoS2/Ni-Mn-In device, a conceptual model based on copper ion migration, is proposed and well explained. The resistive switching parameters such as the set voltage, LRS and HRS resistances, are also investigated in a temperature range overlapping with the martensite phase transformation temperatures of the bottom ferromagnetic shape memory alloy (Ni-Mn-In) electrode. It provides temperature as an extra degree of freedom to modulate the resistive switching characteristics of the fabricated device. The Cu/MoS2/Ni-Mn-In device shows a decent endurance of 500 and a long retention of 103. These results demonstrate the feasibility of the MoS2 based devices for futuristic tunable nonvolatile resistive random access memory applications.

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This report is on the diameter dependent thermal sensitivity variation trend of Ni/4H-nSiC Schottky barrier diode (SBD) temperature sensors. Scaled SBDs of 2, 1.6, and 1.2 mm in diameter were fabricated using standard photolithography process comprising a field plate and a guard ring as edge terminations on the same epitaxial wafer. Taking into consideration the heat loss and power consumption, the thermal sensitivities of the fabricated SBDs were measured in the current range from 1 μA to 50 pA. The temperature was varied from 273 to 473 K in step of 25 K. An authoritative consequence of the present study is the observed increase in thermal sensitivity with the diameter of the fabricated SBDs. An exhaustive investigation confirms that in all diodes, there exist nanosized patches, which assumed to have different barrier heights and hence ascertained to be the main cause of anomalies in thermal sensitivity variation with diode size. Taking into account the effective area of these patches, theoretically fitted I–V curves to experimental data show that the numbers of patches were higher in diode with least size and decrease with the increase in the size of the diode. The corresponding barrier heights of these patches were found to be distributed in a Gaussian like manner at the fabricated Ni/4H-nSiC interface with least standard deviation (σ0) in the diode of maximum size.

In this report, the ferromagnetic shape memory alloy (Ni50Mn35In15) and Pb0.96La0.04Zr0.52Ti0.48O3 based bilayer (Ni-Mn-In/PLZT (260 nm/300 nm)), trilayer (Ni-Mn-In/PLZT/Ni-Mn-In (130 nm/300 nm/130 nm)) and four-layer (Ni-Mn-In/PLZT/Ni-Mn-In/PLZT (130 nm/150 nm/130 nm/150 nm)) multiferroic heterostructures with equal thickness ratios have been fabricated over Si substrates via DC/RF magnetron sputtering technique. The in-plane and out-of-plane magnetic hysteresis curves show the anisotropic nature of the ferromagnetic layer. The anisotropic magnetoelectric coupling characteristics have been investigated for all the fabricated devices by recording the induced magnetoelectric coupling voltages under both parallel and perpendicular applied magnetic fields to the plane of the device. Compared to all fabricated heterostructures, the trilayer structure exhibits the highest magnetoelectric coupling coefficients with 1.56 V/(cm Oe)-1 and 2.01 V/(cm Oe)-1 in longitudinal and transverse configurations, respectively. This anisotropic nature of magnetoelectric coupling can be used to measure the applied magnetic field direction. The rarely reported anisotropic AC magnetic field sensing parameters of the fabricated devices like Pearson’s r, sensitivity, and inaccuracy have been calculated. The trilayer device exhibits excellent AC magnetic field sensing parameters with inaccuracy, sensitivity, and linearity of 1.856% full-scale output (FSO), 0.63 mV cm−1 and 0.9993 in longitudinal configuration while 1.755% FSO, 1.18 mV Oe−1, and 0.9993 in the transverse configuration, respectively. Such nanoscale ferromagnetic shape memory alloys based symmetric multilayered multiferroic heterostructures pave the way for the design and development of futuristic MEMS magnetoelectric magnetic field sensor to detect the magnetic field and its spatial orientation.

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