Effect of Magnetic Field on the Lock-In Transition in Cupric Oxide

1998 ◽  
Vol 12 (02n03) ◽  
pp. 85-89
Author(s):  
T. V. Chandrasekhar Rao ◽  
S. B. Ota ◽  
V. C. Sahni
Keyword(s):  
Magnetic Field ◽  
Transition Temperature ◽  
Cupric Oxide ◽  
Squid Magnetometer ◽  
Clapeyron Equation ◽  
Magnetization Measurements ◽  
Temperature Range ◽  
Lock In ◽  
The Magnetic Field

We present magnetization measurements on polycrystalline CuO over the temperature range 5–300 K using a SQUID magnetometer. The change in sample magnetization at the lock-in transition temperature (212.6 K) as a function of the magnetic field has been found to scale with the field. The results are analyzed in terms of the magnetic analogue of the Clausius–Clapeyron equation.

Optimization of Sample Holder Materials for Sensitive Magnetometry Measurements at Low Temperatures

2004 ◽  
Vol 825 ◽  
Author(s):  
I. Bossi ◽  
N.R. Dilley ◽  
J. R. O'Brien ◽  
S. Spagna
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
Magnetic Response ◽  
Sample Holder ◽  
Magnetization Measurements ◽  
Temperature Range ◽  
Paramagnetic Impurities ◽  
Fused Quartz

AbstractMagnetization measurements were performed as a function of magnetic field H and temperature T on samples of nine different materials including clear fused quartz, cartridge brass, G-10 glass-reinforced epoxy, acetal homopolymer, glass-filled acetal, phenolic, and other plastics. A small yet distinct amount of ferromagnetic or paramagnetic impurities is observed in all the materials investigated in this study except quartz. In contrast, the magnetic response of quartz is typical of a diamagnet over the temperature range 5 K to 300 K. The volume susceptibility is equal to −4.4×10−7 (cgs) over the whole temperature range.

scholarly journals Описание колоссального магнитосопротивления La-=SUB=-1.2-=/SUB=-Sr-=SUB=-1.8-=/SUB=-Mn-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- на основе "спин-поляронного" и "ориентационного" механизмов проводимости в парамагнитной области температур

2020 ◽  
Vol 62 (5) ◽  
pp. 669
Author(s):  
С.А. Гудин ◽  
Н.И. Солин
Keyword(s):  
Magnetic Field ◽  
Colossal Magnetoresistance ◽  
Main Role ◽  
Spin Polaron ◽  
Temperature Range ◽  
Conduction Mechanisms ◽  
Theoretical Investigations ◽  
Temperature Dependences ◽  
The Magnetic Field ◽  
Good Agreement

Experimental and theoretical investigations of the resistance of the La1.2Sr1.8Mn2O7 single crystal in magnetic fields from 0 to 90 kOe and in the temperature range from 75 to 300 K has been studied. The magnetoresistance is determined by the “spin-polaron” and “orientation” conduction mechanisms. Using the method of separating contributions to the magnetoresistance from several conduction mechanisms, the observed magnetoresistance of La1.2Sr1.8Mn2O7 manganite in the temperature range of 75-300 K is described, good agreement between the calculated and experimental data is obtained. In a magnetic field of 0 and 90 kOe, the temperature dependences of the size of the spin polaron (in relative units) are calculated for the temperature range 75–300 K. It is shown, that the КМС value is determined by an increase in the linear size of the spin polaron (along the magnetic field), i.e. the main role in the magnitude of the colossal magnetoresistance is made by the change in the size of the magnetic inhomogeneities of the crystal.

CRITICAL FIELD AND MAGNETORESISTANCE OF SINGLE CRYSTAL TmNi2B2C

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3715-3717 ◽  
Author(s):  
D. G. NAUGLE ◽  
K. D. D. RATHNAYAKA ◽  
K. CLARK ◽  
P. C. CANFIELD
Keyword(s):  
Magnetic Field ◽  
Transition Temperature ◽  
Single Crystal ◽  
Critical Field ◽  
Superconducting Transition Temperature ◽  
Magnetic Transition ◽  
Upper Critical Field ◽  
Superconducting Transition ◽  
Large Anisotropy ◽  
The Magnetic Field

In-plane resistance as a function of magnitude and direction of the magnetic field and the temperature has been measured for TmNi2B2C from above the superconducting transition temperature at 10.7 K to below the magnetic transition TN=1.5 K. The superconducting upper critical field HC2(T) exhibits a large anisotropy and structure in the vicinity of TN. The magnetoresistance above TC is large and changes sign as the direction of the magnetic field is rotated from in-plane to parallel with the c-axis.

SOME OBSERVATIONS ON ROCK MAGNETISM

Geophysics ◽  
1958 ◽  
Vol 23 (2) ◽  
pp. 285-298 ◽  
Author(s):  
Lynn G. Howell ◽  
Joseph D. Martinez ◽  
E. H. Statham
Keyword(s):  
Magnetic Field ◽  
Magnetic Material ◽  
Magnetic Susceptibility ◽  
Transition Temperature ◽  
Iron Ore ◽  
Rock Magnetism ◽  
Bedding Plane ◽  
Metamorphic Rocks ◽  
The Magnetic Field ◽  
Red Bed

It seems that in general the plane of maximum magnetic susceptibility lies in the bedding plane for sediments and in the plane of foliation for metamorphic rocks; there is, also, a tendency for the remanent vector to lie in the plane of foliation in the latter. In the case of chemical deposits, the question is raised as to whether the hematite crystal growth is controlled by the magnetic field. Since pure hematite crystals are paramagnetic along the ternary axis, the remanent vector lies in the basal plane perpendicular to this axis, which being the plane of ferromagnetism, is also the plane of maximum susceptibility. We have investigated chemically deposited hematite in the Clinton iron ore of Silurian Age. Although the remanent vector lies close to the plane of maximum susceptibility, this plane, unfortunately, is also the bedding plane. Several other hematite‐bearing formations show a direction of magnetization close to the bedding plane. Measurements of magnetization and susceptibility anisotropy of samples cooled below the transition temperature for hematite have been made with no conclusive results other than indications of the presence of hematite in some cases. Samples from the Hazel formation of pre‐Cambrian Age have been investigated. The planes of maximum susceptibility for this slightly metamorphosed red bed dip at various angles, and thus a system of microfractures containing magnetic material is suggested as a possible explanation. Pole locations for the Clinton iron ore and the Hazel are presented.

FERROMAGNETIC RESONANCE IN TERFENOL-D AT 17 GHz

2001 ◽  
Vol 15 (24n25) ◽  
pp. 3266-3269 ◽  
Author(s):  
G. DEWAR ◽  
S. PAGEL ◽  
P. SOURIVONG
Keyword(s):  
Magnetic Field ◽  
Ferromagnetic Resonance ◽  
Elastic Strain ◽  
Magnetocrystalline Anisotropy ◽  
Anisotropy Constant ◽  
Temperature Range ◽  
Torque Measurements ◽  
The Magnetic Field

Ferromagnetic resonance measurements have been performed on several samples of Terfenol-D ( Dy0.73Tb0.27Fe1.95 ) at 16.95 GHz and over the temperature range 293 to 305 K. We find that the first magnetocrystalline anisotropy constant, obtained from one sample under nearly zero stress, is K1 = (-1.4±1.0)× l06 erg/cm 3 at 294 K. Our measurement is distinct from quasistatic torque measurements in that the lattice does not deform during the measurement and, hence, the anisotropy contribution due to magnetoelastic strain does not enter. The bare anisotropy constant, unmodified by static elastic strain, is [Formula: see text] and [Formula: see text]. The samples exhibited hysteresis; the position of FMR shifted by 4.0 kOe between measurements made with the magnetic field increasing and those made with the field decreasing.

Messungen an Fe57 in Calciumaluminatferriten mit Hilfe des Mößbauer-Effekts

1966 ◽  
Vol 21 (6) ◽  
pp. 831-835 ◽  
Author(s):  
F. Wittmann ◽  
F. Pobell
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Calcium Aluminate ◽  
Isomeric Shift ◽  
Temperature Range ◽  
Octahedral Sites ◽  
The Magnetic Field ◽  
Curie Temperatures

Measurements of the MÖSSBAUER-effect were made on Calcium-Aluminate-Ferrites [2 CaO · (Al2O3) x · (Fe2O3) 1-x] in the temperature range 4.2 °K ≦ Τ ≦ 700 °K. Ferrites with x=0, 1/3, 1/2 were made by sintering. The isomeric-shift is the same for the three ferrites, whereas the quadrupol-splitting is a function of x : ε1 (x=0) = (1.38 ± 0.05) mm/sec, ε2 (x=⅓) = (1.44 ± 0.05) mm/sec, ε3 (x =½) = (1.64 ± 0.05) mm/sec. The CURIE temperatures are Θ1 = (615 ± 4) °K, Θ2 = (490 ± 5) °K and Θ3= (398 ± 10) °K. For T=0 °K the extrapolated values of the magnetic field are independent of x : H0 (tet) = (505 ± 10) kOe and H0 (oct) = (555 ± 10) kOe at the tetrahedral and octahedral sites respectively. Under the assumption of an axial symmetric electric field gradient we calculated the angles between the electric field gradient and the magnetic field at the two lattice sites.

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