Study of Thermal Conductivity due to Spins in One-Dimensional Spin Systems AFeX3 (A=Rb, Cs; X=Cl, Br)

Large contributions of the thermal conductivity due to spins, κspin, in low-dimensional spin systems are expected to be utilized as highly thermal conducting materials. One-dimensional spin system RbFeCl3 with ferromagnetic chains and CsFeBr3 with antiferromagnetic chains in magnetic fields have been prepared in order to observe the contribution of κspin to the value of thermal conductivity. The temperature dependence of the thermal conductivity parallel to spin chains along the c-axis, κ//c, of RbFeCl3 enhanced around 3 K and 10 K by the application of magnetic field. In the thermal conductivity perpendicular to c-axis, κ⊥c, of RbFeCl3, on the other hand, it has been found that only one peak around 3 K is enhanced by the application of magnetic field. Since κ⊥c is mainly owing to the thermal conductivity due to phonons, κphonon, it has been concluded the peak of κ//c around 10 K in magnetic fields is due to the contribution of κspin. For CsFeBr3, it has been found that κ//c shows two peaks around 3 K and 25 K while κ⊥c shows one peak around 12 K in zero field. This indicates that there is a marked contribution of κspin to κ//c. κ⊥ However, the details of the marked contribution of κspin to κ//c are not yet clear, since κ//c has been suppressed by the application of magnetic field in contrast with the enhancement of the thermal conductivity in RbFeCl3.

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Low-Dimensional Critical Behaviors and Competition Between Order Parameters in the Organic Metal (Tmtsf)2ClO4

MRS Proceedings ◽

10.1557/proc-173-205 ◽

1989 ◽

Vol 173 ◽

Cited By ~ 1

Author(s):

F. Pesty ◽

P. Garoche ◽

M. Heritier

Keyword(s):

Magnetic Field ◽

Thermal Conductivity ◽

Specific Heat ◽

High Field ◽

Density Wave ◽

Second Order ◽

Metallic State ◽

Transition Line ◽

One Dimensional ◽

Low Dimensional

ABSTRACTIn low-dimensional conductors, the instability of the metallic state can lead to the formation at low temperature of a spin density wave induced by the magnetic field (FISDW). The transition results from the complex interplay between the one dimensional instability of the electronic gas and the quantization of the magnetic field’s flux. This second-order phase-transition line has been investigated by measuring both specific heat and thermal conductivity along the c* direction. The mean-field jump and the gap value have been deduced respectively from the anomaly and the exponential decay of the electronic specific heat. The coupling strength λ has been evaluated, and the λ > 0.3 value indicates clearly a strong coupling behavior at high field. Below 8 teslas, the specific heat displays a double anomaly in relation with the competition between subphases. Above the second-order transition line, critical fluctuations are observed on both specific heat and lattice thermal conductivity. Along this line, one-dimensional fluctuations increase with increasing magnetic field. It is proposed that the very high field reentrance of the metal is to be related to enhancement of the 1D fluctuations.

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Hamiltonian Approach to Magnetic Fields with Toroidal Surfaces

Zeitschrift für Naturforschung A ◽

10.1515/zna-1985-1001 ◽

1985 ◽

Vol 40 (10) ◽

pp. 959-967

Author(s):

A. Salat

Keyword(s):

Magnetic Field ◽

Hamiltonian System ◽

Magnetic Fields ◽

Constant Pressure ◽

Time Dependent ◽

Hamiltonian Approach ◽

One Dimensional ◽

Mhd Equilibrium ◽

Magnetic Surfaces ◽

Rotational Transform

The equivalence of magnetic field line equations to a one-dimensional time-dependent Hamiltonian system is used to construct magnetic fields with arbitrary toroidal magnetic surfaces I = const. For this purpose Hamiltonians H which together with their invariants satisfy periodicity constraints have to be known. The choice of H fixes the rotational transform η(I). Arbitrary axisymmetric fields, and nonaxisymmetric fields with constant η(I) are considered in detail.Configurations with coinciding magnetic and current density surfaces are obtained. The approach used is not well suited, however, to satisfying the additional MHD equilibrium condition of constant pressure on magnetic surfaces.

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FROM RELATIVISTIC VECTOR MESONS IN CONSTANT MAGNETIC FIELDS TO NONRELATIVISTIC (PSEUDO)SUPERSYMMETRIES

International Journal of Modern Physics A ◽

10.1142/s0217751x95001315 ◽

1995 ◽

Vol 10 (19) ◽

pp. 2783-2797 ◽

Cited By ~ 8

Author(s):

J. BECKERS ◽

N. DEBERGH

Keyword(s):

Magnetic Field ◽

Quantum Mechanics ◽

Magnetic Fields ◽

Constant Magnetic Field ◽

Vector Mesons ◽

One Dimensional ◽

Recent Developments

Results coming from the study of relativistic vector mesons interacting with a constant magnetic field are examined through Johnson-Lippmann implications on one-dimensional oscillatorlike systems. We obtain specific nonrelativistic Hamiltonians showing new properties in quantum mechanics and leading to superpositions of bosons and pseudofermions. Moreover, two “potentials” are introduced and discussed in comparison with recent developments usually obtained in p=2 parasupersymmetric quantum mechanics. Pseudofermions are also examined, particularly with respect to orthofermions.

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PULSE-FIELD EXPERIMENTS ON THE SPIN-LATTICE INTERACTION IN LOW-DIMENSIONAL SPIN SYSTEMS

International Journal of Modern Physics B ◽

10.1142/s0217979202014449 ◽

2002 ◽

Vol 16 (20n22) ◽

pp. 3369-3372

Author(s):

B. WOLF ◽

S. ZHERLITSYN ◽

S. SCHMIDT ◽

B. LÜTHI ◽

M. LANG

Keyword(s):

Magnetic Field ◽

Spin System ◽

Field Experiments ◽

Resonant Interaction ◽

Quantum Spin ◽

Spin Systems ◽

Pulse Field ◽

Quantum Spin System ◽

Magnetic Excitations ◽

Low Dimensional

Low-dimensional spin systems reveal new and unexpected physical phenomena such as distinct plateaus in the magnetization as a function of magnetic field. In this paper we present ultrasonic measurements for the quasi-two-dimensional spin system SrCu2(BO3)2 in magnetic fields up to 50 T. From this technique we obtained detailed information about the spin state, the magnetic excitations and their interaction with phonons. The dimerized quantum-spin system SrCu2(BO3)2 exhibits plateaus in the magnetization and shows surprisingly strong magneto-elastic effects as a function of temperature and magnetic field. The pronounced elastic anomalies indicate a resonant interaction between the sound wave and the magnetic excitations.

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Thermal conductivity of one-dimensional spin- systems

Physica B Condensed Matter ◽

10.1016/j.physb.2005.01.432 ◽

2005 ◽

Vol 359-361 ◽

pp. 1394-1396 ◽

Cited By ~ 10

Author(s):

F. Heidrich-Meisner ◽

A. Honecker ◽

D.C. Cabra ◽

W. Brenig

Keyword(s):

Thermal Conductivity ◽

Spin Systems ◽

One Dimensional

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ONE AND QUASI-ONE DIMENSIONAL SPIN SYSTEMS

Modern Physics Letters A ◽

10.1142/s0217732303012544 ◽

2003 ◽

Vol 18 (33n35) ◽

pp. 2329-2336 ◽

Cited By ~ 1

Author(s):

Elisa Ercolessi

Keyword(s):

Condensed Matter ◽

Quantum Spin ◽

Spin Systems ◽

Spin Chains ◽

Famous Conjecture ◽

One Dimensional ◽

Conformal Field ◽

Quantum Spin Models ◽

Low Dimensional ◽

Antiferromagnetic Spin

Quantum spin models represent one of the most studied examples of application of low-dimensional field theories to condensed matter systems. In this paper we will review some chapters of this hystory, that dates back to the early '80, when Haldane put forward his by now famous conjecture on antiferromagnetic spin chains, and reaches the present days, with the most advanced applications of integrable models and conformal field theory.

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Effects of magnetic-field-induced chiral-spin interactions on quasi-one-dimensional spin systems

Physical Review B ◽

10.1103/physrevb.63.054441 ◽

2001 ◽

Vol 63 (5) ◽

Cited By ~ 7

Author(s):

R. Chitra ◽

R. Citro

Keyword(s):

Magnetic Field ◽

Spin Systems ◽

One Dimensional ◽

Spin Interactions

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Effect of magnetic fields on cryptochrome-dependent responses in Arabidopsis thaliana

Journal of The Royal Society Interface ◽

10.1098/rsif.2008.0519 ◽

2009 ◽

Vol 6 (41) ◽

pp. 1193-1205 ◽

Cited By ~ 53

Author(s):

Sue-Re Harris ◽

Kevin B. Henbest ◽

Kiminori Maeda ◽

John R. Pannell ◽

Christiane R. Timmel ◽

...

Keyword(s):

Magnetic Field ◽

Arabidopsis Thaliana ◽

Magnetic Fields ◽

Low Frequency ◽

Zero Field ◽

Experimental Conditions ◽

Replication Studies ◽

Weak Magnetic Fields ◽

Simultaneous Control ◽

Independent Replication

The scientific literature describing the effects of weak magnetic fields on living systems contains a plethora of contradictory reports, few successful independent replication studies and a dearth of plausible biophysical interaction mechanisms. Most such investigations have been unsystematic, devoid of testable theoretical predictions and, ultimately, unconvincing. A recent study, of magnetic responses in the model plant Arabidopsis thaliana , however, stands out; it has a clear hypothesis—that seedling growth is magnetically sensitive as a result of photoinduced radical-pair reactions in cryptochrome photoreceptors—tested by measuring several cryptochrome-dependent responses, all of which proved to be enhanced in a magnetic field of intensity 500 μT. The potential importance of this study in the debate on putative effects of extremely low-frequency electromagnetic fields on human health prompted us to subject it to the ‘gold standard’ of independent replication. With experimental conditions chosen to match those of the original study, we have measured hypocotyl lengths and anthocyanin accumulation for Arabidopsis seedlings grown in a 500 μT magnetic field, with simultaneous control experiments at 50 μT. Additionally, we have determined hypocotyl lengths of plants grown in 50 μT, 1 mT and approximately 100 mT magnetic fields (with zero-field controls), measured gene ( CHS , HY5 and GST ) expression levels, investigated blue-light intensity effects and explored the influence of sucrose in the growth medium. In no case were consistent, statistically significant magnetic field responses detected.

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Analog Video Magnetograms in Real Time

Symposium - International Astronomical Union ◽

10.1017/s0074180900022427 ◽

1971 ◽

Vol 43 ◽

pp. 76-83 ◽

Cited By ~ 7

Author(s):

R. C. Smithson ◽

R. B. Leighton

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Solar Magnetic Field ◽

Solar Spectrum ◽

Zeeman Splitting ◽

The Other ◽

Line Of Sight ◽

Zero Field ◽

The Sun ◽

Solar Magnetic Fields

For many years solar magnetic fields have been measured by a variety of techniques, all of which exploit the Zeeman splitting of lines in the solar spectrum. One of these techniques (Leighton, 1959) involves a photographic subtraction of two monochromatic images to produce a picture of the Sun in which the line-of-sight component of the solar magnetic field appears as various shades of gray. In a magnetogram made by this method, zero field strength appears as neutral gray, while magnetic fields of one polarity or the other appear as lighter or darker areas, respectively. Figure 1 shows such a magnetogram.

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