Nitrogen embedded ZnO:N films prepared by pulsed laser deposition exhibit significant ferromagnetism. The nitrogen ions contained in ZnO confirmed by Secondary Ion Microscopic Spectrum and Raman experiments and the embedded nitrogen ions can be regarded as defects. According to the experiment results, a mechanism is proposed based on one of the electrons in the completely filled dorbits of Zn that compensates the dangling bonds of nitrogen ions and leads to a net spin of one half in the Zn orbits. These one half spins strongly correlate with localized electrons that are captured by defects to form ferromagnetism. Eventually, the magnetism of nitrogen embedded ZnO:N films could be described by a bound magnetic polaron model.

No abstract

Observation of the room temperature ͑RT͒ anomalous Hall effect ͑AHE͒ and ferromagnetism in semiconducting like ͑carrier concentration ϳ10 19 cm −3 ͒ Co-doped ZnO samples is reported. These small AHE signals match quantitatively with the magnetic hysteresis and can be correspondent to the intrinsic diluted magnetic oxide ͑DMO͒ effect with spin polarized carriers. The contribution to the DMO effect depends on the types of carriers and how they incorporated into the electric conduction, magnetic coupling, and the coupling between them. These findings can provide useful information in the study of the origin of RT ferromagnetism in ZnO-based DMO and for further application in spintronics.

No abstract

Exchange bias and enhanced coercivity in phase separated La0.45Sr0.55MnO3 and Pr0.55(Ca0.65S0.35)

Magnetic properties of Ru-deficient strain relaxed SrRuO3 films have been investigated. The ferromagnetic transitions drop off from 138 to 100 K with expansion of unit cell volume due to the Ru vacancies. A secondary transition starts appearing near to the bulk transition temperature of 155 K, indicating the two different Ru-deficient regions which result in an exchange structure. Anomalous variation of the saturation magnetization with the unit cell volume could be originated from the stabilization of the high spin Ru+4 states due to the Ru-vacancy and the induced crystal lattice distortions from c/a > 1 to c/a < 1.

Articles you may be interested inStrain induced tunable anisotropic magnetoresistance in La0.67Ca0.33MnO3/BaTiO3 heterostructures

A photodetector with high responsivity has been fabricated with a high quality Y1Ba2Cu3O7−δ film on a regular SrTiO3 (100) substrate that has no thinning or etching. The film exhibits a precipitation-free morphology and has an extremely smooth surface having a rms roughness smaller than 5 nm. The film was patterned into a 25×650 μm2 long microbridge by a conventional photolithography technique. The Tco of the microbridge can be tuned by applying different bias currents, which results in a tunable operation temperature of the photodetector at 77.35±1 K. This makes it operationally more practical and economical. The noise voltage at 10 mA bias current is less than the resolution of our setup, 15 nV  Hz−0.5. A high responsivity of 2.3×103 V/W was obtained when a bias current of 8 mA and a low power density He–Ne laser of 0.08 J/cm2 s chopped at 2 Hz were applied on the microbridge at 77.35 K. Under the same condition, the noise equivalent power (NEP) and detectivity (D*) have been measured to be 4.34×10−12 W Hz−0.5 and 3×109 cm Hz0.5 W−1, respectively.