The magnetostructural coupling between the structural and the magnetic transition has a crucial role in magnetoresponsive effects in a martensitic-transition system. A combination of various magnetoresponsive effects based on this coupling may facilitate the multifunctional applications of a host material. Here we demonstrate the feasibility of obtaining a stable magnetostructural coupling over a broad temperature window from 350 to 70 K, in combination with tunable magnetoresponsive effects, in mnniGe:Fe alloys. The alloy exhibits a magneticfield-induced martensitic transition from paramagnetic austenite to ferromagnetic martensite. The results indicate that stable magnetostructural coupling is accessible in hexagonal phasetransition systems to attain the magnetoresponsive effects with broad tunability.

Ni-Mn-In-Co single-crystalline particles for magnetic shape memory composites Appl. Phys. Lett. 95, 152503 (2009); 10.1063/1.3249585Entropy change and effect of magnetic field on martensitic transformation in a metamagnetic Ni-Co-Mn-In shape memory alloy

Wheat (Triticum aestivum L.) incurs significant yield losses from powdery mildew, a major fungal disease caused by Blumeria graminis f. sp. tritici (Bgt). enhanced disease resistance1 (EDR1) plays a negative role in the defense response against powdery mildew in Arabidopsis thaliana; however, the edr1 mutant does not show constitutively activated defense responses. This makes EDR1 an ideal target for approaches using new genome-editing tools to improve resistance to powdery mildew. We cloned TaEDR1 from hexaploid wheat and found high similarity among the three homoeologs of EDR1. Knock-down of TaEDR1 by virus-induced gene silencing or RNA interference enhanced resistance to powdery mildew, indicating that TaEDR1 negatively regulates powdery mildew resistance in wheat. We used CRISPR/Cas9 technology to generate Taedr1 wheat plants by simultaneous modification of the three homoeologs of wheat EDR1. No off-target mutations were detected in the Taedr1 mutant plants. The Taedr1 plants were resistant to powdery mildew and did not show mildew-induced cell death. Our study represents the successful generation of a potentially valuable trait using genome-editing technology in wheat and provides germplasm for disease resistance breeding.

Plant defense responses are tightly controlled by many positive and negative regulators to cope with attacks from various pathogens. Arabidopsis (Arabidopsis thaliana) ENHANCED DISEASE RESISTANCE2 (EDR2) is a negative regulator of powdery mildew resistance, and edr2 mutants display enhanced resistance to powdery mildew (Golovinomyces cichoracearum). To identify components acting in the EDR2 pathway, we screened for edr2 suppressors and identified a gain-of-function mutation in SIGNAL RESPONSIVE1 (SR1), which encodes a calmodulin-binding transcription activator. The sr1-4D gain-of-function mutation suppresses all edr2-associated phenotypes, including powdery mildew resistance, mildew-induced cell death, and ethylene-induced senescence. The sr1-4D single mutant is more susceptible to a Pseudomonas syringae pv tomato DC3000 virulent strain and to avirulent strains carrying avrRpt2 or avrRPS4 than the wild type. We show that SR1 directly binds to the promoter region of NON-RACE-SPECIFIC DISEASE RESISTANCE1 (NDR1), a key component in RESISTANCE TO PSEU-DOMONAS SYRINGAE2-mediated plant immunity. Also, the ndr1 mutation suppresses the sr1-1 null allele, which shows enhanced resistance to both P. syringae pv tomato DC3000 avrRpt2 and G. cichoracearum. In addition, we show that SR1 regulates ethylene-induced senescence by directly binding to the ETHYLENE INSENSITIVE3 (EIN3) promoter region in vivo. Enhanced ethylene-induced senescence in sr1-1 is suppressed by ein3. Our data indicate that SR1 plays an important role in plant immunity and ethylene signaling by directly regulating NDR1 and EIN3.

Shape memory and ferromagnetic shape memory effects in single-crystal Ni 2 MnGa thin films Heusler alloy Mn 2 NiGa has been developed by synthesizing a series of ferromagnetic shape memory alloys Mn 25+x Ni 50−x Ga 25 ͑x = 0-25͒. Mn 2 NiGa exhibits a martensitic transformation around room temperature with a large thermal hysteresis up to 50 K and a lattice distortion as large as 21.3% and has a quite high Curie temperature of 588 K. The martensite shows a high-saturated field up to 2 T. The excellent two-way shape memory behavior with a strain of 1.7% was observed in the single crystal Mn 2 NiGa. The magnetic-field-controlled effect created a total strain up to 4.0% and changed the sign of the shape deformation effectively.

We report on structural, magnetic, transport, and spin-polarization measurements of the Heusler alloys Co 2 MnSi and NiMnSb. Laue diffraction patterns confirm the single-crystal nature of Co 2 MnSi. Roomtemperature transport measurements show a negative magnetoresistance in NiMnSb. Point-contact Andreev reflection measurements of the spin polarization yield polarization values for Co 2 MnSi and NiMnSb of 56% and 45%, respectively. Temperature dependence of resistivity for Co 2 MnSi reveals a relatively large residual resistivity ratio ( 293 K / 5 K ) typical of single-crystal Heusler alloys. In NiMnSb, resistivity and magnetization as a function of temperature show evidence of a magnetic phase transition near 90 K.

A large magnetic entropy change ͉⌬S͉ has been observed in Heusler alloy Ni 52.6 Mn 23.1 Ga 24.3 single crystal near the martensitic structural transition temperature of 300 K with applied field along ͓001͔ direction. The obtained ͉⌬S͉ under an applied field of 5 T reaches 18.0 J/Kg K ͑corresponding 146 mJ/cm 3 K). A more important result is that ͉⌬S͉ can achieve constant increase of 4.0 J/Kg K for the field increase of every tesla. The very large magnetic entropy change is attributed to the abrupt change of magnetization when the first-order martensitic-austensitic structural transition takes place. The phenomena of the large magnetic entropy change and the easy adjustment of the martensitic-austensitic transition-temperature indicate that the non-rare-earth based Ni-Mn-Ga single-crystal materials may have potential applications as magnetic refrigerants.

We study the electronic structures and magnetic properties of Mn 2 CoZ ͑Z =Al,Ga,In,Si,Ge,Sn,Sb͒ compounds with Hg 2 CuTi-type structure using first-principles full-potential linearized-augmented plane-wave calculations. It is found that the compounds with Z = Al, Si, Ge, Sn, and Sb are half-metallic ferrimagnet. Experimentally, we successfully synthesized the Mn 2 CoZ ͑Z =Al,Ga,In,Ge,Sn,Sb͒ compounds. Using the x-ray diffraction method and Rietveld refinement, we confirm that these compounds form Hg 2 CuTi-type structure instead of the conventional L2 1 structure. Based on the analysis on the electronic structures, we find that there are two mechanisms to induce the minority-spin band gap near the Fermi level, but only the d-d band gap determines the final width of the band gap. The magnetic interaction is quite complex in these alloys. It is the hybridization between the Mn͑C͒ and Co atom that dominates the magnitude of magnetic moment of the Co atom and the sign of the Mn͑B͒-Co exchange interaction. The Mn 2 CoZ alloys follow the Slater-Pauling rule M H = N V − 24 with varying Z atom. It was further elucidated that the molecular magnetic moment M H increases with increasing valence concentration only by decreasing the antiparallel magnetic moment of Mn͑C͒, while the magnetic moments of Mn͑B͒ and Co are unaffected.