arXiv subjects

C. C. Kuo

Publications and source records attributed to C. C. Kuo.

4 recordsLinked to original sources

arXiv2015

Magnetic phase transitions in Ta/CoFeB/MgO multilayers

We study thin films and magnetic tunnel junction nanopillars based on Ta/Co$_{20}$Fe$_{60}$B$_{20}$/MgO multilayers by electrical transport and magnetometry measurements. These measurements suggest that an ultrathin magnetic oxide layer forms at the Co$_{20}$Fe$_{60}$B$_{20}$/MgO interface. At approximately 160 K, the oxide undergoes a phase transition from an insulating antiferromagnet at low temperatures to a conductive weak ferromagnet at high temperatures. This interfacial magnetic oxide is expected to have significant impact on the magnetic properties of CoFeB-based multilayers used in spin torque memories.

cond-mat.mtrl-sci↗

arXiv2007

Multi-phonon Raman scattering in GaN nanowires

UV Raman scattering studies show longitudinal optical (LO) mode up to 4th order in wurtzite GaN nanowire system. Frohlich interaction of electron with the long range electrostatic field of ionic bonded GaN gives rise to enhancement in LO phonon modes. Good crystalline quality, as indicated by the crystallographic as well as luminescence studies, is thought to be responsible for this significant observation. Calculated size dependence, incorporating size corrected dielectric constants, of electron-phonon interaction energy agrees well with measured values and also predict stronger interaction energy than that of the bulk for diameter below ~3 nm.

cond-mat.mtrl-sci↗

arXiv2006

Studies of $γγ\toΛ\barΛ,Σ^0\bar{Σ^0}$ production at Belle

Cross sections for hyperon pair production from two-photon collisions, $γγ\toΛ\barΛ,Σ^0\bar{Σ^0}$, are measured in the 2-4 GeV energy region at Belle, using 464 fb$^{-1}$ of data. A contribution from the intermediate resonance $η_c(1S)$ is observed, and the products of the two-photon width of the $η_c(1S)$ and its branching ratios to $Λ\barΛ$ and $Σ^0\bar{Σ^0}$ are measured. The results will help test QCD models.

hep-ex↗

arXiv2005

Measurement of gamma gamma -> p p-bar production at Belle

A high precision study of the process gamma gamma -> p p-bar has been performed using a data sample of 89/fb collected with the Belle detector at the KEKB e+e- collider. The cross section of p p-bar production has been measured at two-photon center-of-mass (c.m.) energies between 2.025 and 4.0 GeV and in the c.m. angular range of |cos(theta^*)|<0.6. Production of gamma gamma -> eta_c -> p p-bar is observed and the product of the two-photon width of the eta_c and its branching ratio to p p-bar is determined.

hep-ex↗