Low temperature study of field induced antiferro-ferromagnetic transition in Pd doped FeRh

The first order antiferromagnetic (AFM) to ferromagnetic (FM) transition in the functional material Fe49(Rh0.93Pd0.07)51 has been studied at low temperatures and high magnetic fields. We have addressed the non-monotonic variation of lower critical field required for FM to AFM transition. It is shown that critically slow dynamics of the transition dominates below 50 K. At low temperature and high magnetic field, state of the system depends on the measurement history resulting in tunable coexistence of AFM and FM phases. By following cooling and heating in unequal magnetic field (CHUF) protocol it is shown that equilibrium state at 6 Tesla magnetic field is AFM state. Glass like FM state at 6 T (obtained after cooling in 8 T) shows reentrant transition with increasing temperature; viz. devitrification to AFM state followed by melting to FM state.Comment: 8 pages, 7 figure

Room temperature giant baroresistance and magnetoresistance and its tunability in Pd doped FeRh

We report room temperature giant baro-resistance ($\approx$128\%) in $Fe_{49}(Rh_{0.93}Pd_{0.07})_{51}$. With the application of external pressure and magnetic field the temperature range of giant baro-resistance ($\approx$600\% at 5K and 19.9 kbar and 8 Tesla) and magnetoresistance ($\approx$-85\% at 5K and 8 tesla) can be tuned from 5 K to well above room temperature. As the AFM state is stabilized at room temperature under external pressure, it shows giant room temperature magnetoresistance ($\approx$-55\%) with magnetic field. Due to coupled magnetic and latticel changes, the isothermal change in room temperature resistivity with pressure (in the absence of applied magnetic field) as well as magnetic field (under various constant pressure) can be scaled together to a single curve when plotted as a function of X = T + 12.8*H - 7.2*P

Real Space Visualization of Thermomagnetic Irreversibility within Supercooling and Superheating Spinodals in Mn1.85Co0.15SbMn_{1.85}Co_{0.15}Sb using Scanning Hall Probe Microscopy

Phase coexistence across disorder-broadened and magnetic-field-induced first order antiferromagnetic to ferrimagnetic transition in polycrystalline $Mn_{1.85}Co_{0.15}Sb$ has been studied mesoscopically by Scanning Hall Probe Microscope at 120K and up to 5 Tesla magnetic fields. We have observed hysteresis with varying magnetic field and the evolution of coexisting antiferromagnetic and ferrimagnetic state on mesoscopic length scale. These studies show that the magnetic state of the system at low field depends on the path followed to reach 120 K. The low field magnetic states are mesoscopically different for virgin and second field increasing cycle when 120 K is reached by warming from 5K, but are the same within measurement accuracy when the measuring temperature of 120K is reached from 300K by cooling

Evaluation of the growth and yield characteristics of various genotypes of the soybean [Glycine max (L.) Merr.]

Eighteen genotypes of soybean were evaluated in coordinated varietal trial in 2018 and eight genotypes in pre-released varietal trial in 2019 at National Plant Breeding and Genetics Research Centre, Khumaltar, Lalitpur, Nepal. The experimental design was randomized complete block design (RCBD) with three replications. The results showed that the maximum yield was obtained from CN-60 (2858 kg/ha) followed by CM-9133 (2791 kg/ha) in 2018 and CM-9125 (2708 kg/ha) followed by G-1872 (2666 kg/ha) in 2019. Similarly, combined analysis of pre-released varietal trial showed that grain yield was maximum for the LS-22-16-16 (2737.5 kg/ha) followed by G-4508 (2718.5 kg/ha) in 2018 and 2019. Thus, LS-22-16-16 and G-4508 seeds can be delivered to farmers as a farmers acceptance test for the release of soybean variety, while CN-60 and CM-9133 can be promoted to pre-released varietal trial

Multivariate analysis of soybean genotypes

The experiments were conducted using randomized complete block design with three replications at the research field of Agriculture Botany Division, Khumaltar, Lalitpur, Nepal in 2016 and 2017 to evaluate sixteen soybean genotypes using multivariate analysis. The results showed the significant (p <0.05) differences among genotypes for plant height, days to maturity plant and hundred  seeds weight and grain yield. Cluster analysis based on these traits, sixteen soybean genotypes were divided the genotypes into four clusters. The soybean genotypes grouped into cluster 1  showed the  highest value for days to maturity. The genotypes belonged to cluster 2 had the highest values for grain yield and plant height. The principle components analysis showed that PC1 and PC2 having eigen values the highest than unity explained 76.6% of total variability among soybean genotypes attributable to plant height, days to maturity, number of pods/plant, 100 seed weight and grain yield. The genotypes showing wide diversity in cluster and principle component analysis can be used as parents in hybridization programs to maximize the use of genetic diversity and expression of heterosis and develop high yielding soybean varieties

Residual stress induced stabilization of martensite phase and its effect on the magneto-structural transition in Mn rich Ni-Mn-In/Ga magnetic shape memory alloys

The irreversibility of the martensite transition in magnetic shape memory alloys (MSMAs) with respect to external magnetic field is one of the biggest challenges that limits their application as giant caloric materials. This transition is a magneto-structural transition that is accompanied with a steep drop in magnetization (i.e., 'delta M') around the martensite start temperature (Ms) due to the lower magnetization of the martensite phase. In this communication, we show that 'delta M' around Ms in Mn rich Ni-Mn based MSMAs gets suppressed by two orders of magnitude in crushed powders due to the stabilization of the martensite phase at temperatures well above the Ms and the austenite finish (Af) temperatures due to residual stresses. Analysis of the intensities and the FWHM of the x-ray powder diffraction patterns reveals stabilized martensite phase fractions as 97, 75 and 90% with corresponding residual microstrains as 5.4, 5.6 and 3% in crushed powders of the three different Mn rich Ni-Mn alloys, namely, Mn1.8Ni1.8In0.4, Mn1.75Ni1.25Ga and Mn1.9Ni1.1Ga, respectively. Even after annealing at 773 K, the residual stress stabilised martensite phase does not fully revert to the equilibrium cubic austenite phase as the magneto-structural transition is only partially restored with reduced value of 'delta M'. Our results have very significant bearing on application of such alloys as inverse magnetocaloric and barocaloric materials