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Many QTL analyses related to meat production and meat quality traits have been carried out using an [F.sub.2] resource population produced by crossing 2 genetically different breeds. This experiment was intended to investigate whether these QTL were segregating in a purebred Duroc population that had been selected for meat production and meat quality traits during 7 generations. Sus scrofa chromosome 7, for which significant QTL of intramuscular fat and many other traits have already been reported, was studied. The polymorphism of 10 microsatellite markers that were arranged at about 20-cM intervals was investigated on 1,004 pigs. In the selected population, 954 progeny were produced from mating of 99 sires and 286 dams. The QTL analysis for a full-sib family population was examined with the multigeneration pedigree structure of the population. Variance component analysis was used to detect QTL in this population and was examined for the multigeneration pedigree population. In this study, multigenerational pedigree estimated identical by descent coefficients among sibs were produced using Markov chain Monte Carlo methods. The maximum likelihood of odds score was found at the 70-cM position for the LM area, at the 0-cM position for the pork color standard, and at the 120-cM position for the number of thoracic vertebra, but no significant QTL for intramuscular fat were detected on SSC 7. These results indicate that QTL analysis via a variance component method within a purebred population was effective to determine that QTL were segregating in a population of purebred Durocs. Key words: Duroc pig, meat quality, multiple generation, quantitative trait loci, selected population

A study was conducted to analyze the genetic associations among Japanese native chickens based on microsatellite DNA polymorphisms. Nucleotide sequences were obtained from eight microsatellite clones that were randomly chosen. Alleles were assigned based on the size of the polymerase chain reaction product. Results indicated that microsatellite DNA markers are a useful tool for examining genetic relationships among chicken breeds.

Current-induced spin-torque switching was demonstrated on sub-100 nm magnetic tunnel junction devices fabricated on 200 mm substrates utilizing 180 nm complimentary metal–oxide–semiconductor back-end-of-the-line (BEOL) technology. Low resistance-area (RA) product and high tunneling magnetoresistance (TMR) were achieved by using substrates containing a CoFeB free layer and a thin MgO barrier. To obtain the desired sub-100 nm features, photoresist trimming was applied on patterns created by a 248 nm lithography tool. Furthermore, the magnetic stack was defined using an ion beam etch that stopped on the thin MgO barrier. Field-sweep measurements on elliptical devices that are 80 nm wide and 160 nm long indicated RA∼4 Ω μm2 and TMR∼90%. Upon injecting current into the devices while applying an external offset field of 28 Oe, current-induced switching occurred from parallel (P) to antiparallel (AP) state at +1.3 mA, and from AP to P state at -1.25 mA. BEOL process integration on 200 mm substrates enabled statistical analysis of device properties, such as the observation of two breakdown mechanisms in the devices. [ABSTRACT FROM AUTHOR]

We carried out a detailed transmission electron microscopy study on the polycrystalline CoFeB/MgO/CoFeB based magnetic tunnel junction, which shows high magnetoresistance predicted theoretically only in single crystal magnetic tunnel junction. Previously it has been suggested that the crystallinity and degree of texture of MgO tunnel barrier play a crucial role in the polycrystalline system. Here we suggest, on top of the crystallinity issue of MgO, that a grain-to-grain epitaxy of CoFeB/MgO/CoFeB satisfies the prerequisite for the coherent tunneling for the giant tunneling magnetoresistance theoretically predicted. [ABSTRACT FROM AUTHOR]

The Lorentz transmission electron microscopy technique is employed to explain the various magnetic domains of the [La.sub.0.825][Sr.sub.0.175](Mn,Al)[O.sub.3] compounds. The impact of Al substitution on these magnetic domains is also determined.

The bias-voltage and temperature dependence of conductivity arising from the magnon contribution in MgO-based magnetic tunneling junctions (MTJs) with different ferromagnetic electrodes is examined. The abrupt increase in the second derivative conductance at very low biasing voltage in the antiparallel configuration has shown the major role of the surface magnon excitation.

Transmission electron microscope (TEM) is used to study the polycrystalline CoFeB/MgO/CoFeB based magnetic tunnel junction, which has shown high magnetoresistance predicted theoretically only in single crystal magnetic tunnel junction. The results have indicated that a grain-to-grain epitaxy of CoFeB/MgO/CoFeB has satisfied the prerequisite for the coherent tunneling for the theoretically predicted giant tunneling magnetoresistance.

Nonmagnetic Al substitution effect on the stability of a ferromagnetic (FM) metallic state in double-exchange manganite, La0.825Sr0.175MnO3, was investigated by Lorentz transmission electron microscopy (TEM), in combination with magnetic measurements. Both FM transition temperature (Tc) and the rhombohedral-to-orthorhombic (R-to-O) transition temperature (Ts) decreased by a few percent of Al substitution. An in situ Lorentz TEM observation revealed that drastic change of the FM domain structure took place through the R-to-O structural transition. The magnetization decreased slightly at Ts and characteristic spin-glass state is realized in the low-temperature region below Ts. [ABSTRACT FROM AUTHOR]

We investigated bias-voltage and temperature dependence of conductivity arising from the magnon contribution in MgO-based magnetic tunneling junctions (MTJs) with different ferromagnetic electrodes. Second derivative conductance curves showed broad peak structure, which extends from 5 to 200 mV, accompanied by additional peaks at around 23, 54, and 85 mV. The peak intensities were larger for antiparallel configuration than for parallel configuration except that at 85 mV. This difference in the peak intensity was observed to be larger for the MTJs having higher tunneling magnetoresistance ratio, indicating a magnetic origin of these peaks. Abrupt increase in the second derivative conductance at very low biasing voltage in the antiparallel configuration suggests the important role of the surface magnon excitation. [ABSTRACT FROM AUTHOR]