STRUCTURAL AND MAGNETIC FIELD DEPENDENT TRANSPORT PROPERTIES OF p-MnxGe1-x/n-Ge HETEROJUNCTION

2009 ◽  
Vol 23 (17) ◽  
pp. 3579-3585
Author(s):  
SANDIP MAJUMDAR ◽  
AMAL KUMAR DAS ◽  
SAMIT KUMAR RAY

We report the study of a promising Ge -based magnetic heterojunction diode composed of a Mn -doped p - Ge film grown on lightly doped n - Ge film. Magnetic field dependent current rectification of the diode occurs at a low temperature. The measurements of resistivity and magnetoresistance in plane at low temperatures reveal the presence of impurity band in Ge due to Mn doping.

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3216-3219 ◽  
Author(s):  
T. SEKITANI ◽  
N. MIURA ◽  
M. NAITO

We report low-temperature magnetotransport in the normal state of the electron-doped superconductors, Nd 2-x Ce x CuO 4, Pr 2-x Ce x CuO 4, and La 2-x Ce x CuO 4, by suppressing the superconductivity with high magnetic fields. The normal state ρ-T curve shows an up-turn at low temperatures, which has a log T dependence with saturation at lowest temperatures. The up-turn is gradually suppressed with increasing magnetic field, resulting in negative magnetoresistance. We discuss these findings on the basis of the Kondo scattering originating from the magnetic moments of Cu 2+ ions.


1981 ◽  
Vol 42 (C5) ◽  
pp. C5-689-C5-693
Author(s):  
J. D.N. Cheeke ◽  
G. Madore ◽  
A. Hikata

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3171-3174
Author(s):  
F. F. BALAKIREV ◽  
J. B. BETTS ◽  
G. S. BOEBINGER ◽  
S. ONO ◽  
Y. ANDO ◽  
...  

We report low-temperature Hall coefficient in the normal state of the high-Tc superconductor Bi 2 Sr 2-x La x CuO 6+δ. The Hall coefficient was measured down to 0.5 K by suppressing superconductivity with a 60 T pulsed magnetic field. The carrier concentration was varied from overdoped to underdoped regimes by partially substituting Sr with La in a set of five samples. The observed saturation of the Hall coefficient at low temperatures suggests the ability to extract the carrier concentration of each sample. The most underdoped sample exhibits a diverging Hall coefficient at low temperatures, consistent with a depletion of carriers in the insulating ground state. The Hall number exhibits a sharp peak providing additional support for the existence of a phase boundary at the optimal doping.


2005 ◽  
Vol 890 ◽  
Author(s):  
Hiroshi Masumoto ◽  
Takashi Goto

ABSTRACTIt is known that zirconia has excellent thermal and chemical stability, and oxide ion conduction. Therefore, YSZ is expected to be used as oxide ion conducting materials, optical mirror materials, catalytic materials and heat-resistant materials. Zirconia films have been fabricated by PVD (ex. sputtering and laser-ablation), chemical vapor deposition (CVD) and sol-gel methods. CVD is capable to prepare high quality zirconia films with excellent conformal coverage; however, deposition temperature of conventional CVD was usually high than PVD. On the other hand, an electron cyclotron resonance (ECR) plasma is high-activity plasma and high quality crystalline films can be obtained at low temperature by using ECR plasma. In the present study, zirconia thin films were prepared at low temperatures on quartz, polycarbonate and polyimide substrates by ECR plasma MOCVD.Zr-hexafluoroacetylacetonato solution was used as a precursor. The source, which was placed in a glass bubbler, was carried into a reactor by Ar gas. A microwave (2.45 GHz, 500 W) was introduced into the ion chamber through a rectangular wave guide. A magnetic field (875 Gauss) was applied to the ion chamber to satisfy the ECR condition. A mirror-type magnetic field (450 Gauss at the substrate stage) was applied in order to raise a plasma density, which results in an increase of the deposition rates of films. Substrate temperature (Ts) was from 30 to 700 C by water-cooling holder and infrared lamp heater. Microwave power was changed from 0 to 900 W. The deposition time was from 30 to 120 minutes.Cubic, monoclinic and tetragonal zirconia films were obtained over Ts=400 C, and cubic and monoclinic zirconia films were obtained below Ts= C. Cubic and monoclinic zirconia films were also obtained at no heating. The deposition rate increased from 10 to 20 nm/min with increasing Ts from no heating to 600 C. Crystallized zirconia films were obtained on polycarbonate and polyimide substrates at no heating. The ECR plasma was significantly effective to prepare crystallized zirconia films at low temperatures.


1996 ◽  
Vol 79 (11) ◽  
pp. 8488-8492 ◽  
Author(s):  
Jenn‐Fang Chen ◽  
Nie‐Chuan Chen ◽  
Shih‐Yang Chiu ◽  
Pie‐yong Wang ◽  
Wei‐I Lee ◽  
...  

2002 ◽  
Vol 16 (20n22) ◽  
pp. 2960-2963 ◽  
Author(s):  
E. D. JONES ◽  
J. L. RENO ◽  
S. CROOKER ◽  
K. K. BAJAJ ◽  
G. COLI

Low temperature diamagnetic shifts and FWHM linewidths of excitonic transitions in Al x Ga 1-x As alloys are reported as a function of magnetic field (50T maximum) at 4K using photoluminescence spectroscopy. Two samples with aluminum compositions of 5 and 20%, are discussed. The slope of the diamagnetic shift at high fields allows a direct measure of the excitonic reduced mass μ.


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