Magnetic Properties of Linear Chain Systems: Metamagnetism of Single Crystal Co(pyridine)₂CI₂

The metamagnetic behavior of the low temperature properties of single crystal Co(pyridine)2Cl2 is discussed. At 1.25 K oriented single crystals exhibit a two-step metamagnetic transition at applied fields ~0.8 and 1.6 kG along the b-axis, a single transition at ~0.7 kG for applied fields along the a* axis, and a single transition at ~4.2 kG for an applied field along the c axis. Just above the transition fields a moment of 2µB/Co atom is measured for B0 parallel to the a* axis or b axis, and 0.4µB/Co atom is measured for the B0 parallel to the c axis. A large field dependent moment is observed at high fields. Many features of this compound closely mirror the behavior of CoCl2-2H20. However, the Co(pyridine)2Cl 2 has a much smaller interchain exchange, so that many features can be examined at lower fields. The basic features are consistent with a six-sublattice model for the ordered antiferromagnetic system. Measurements of magnetic moment versus temperature show that Co(pyridine)2Cl 2 does not obey a Curie-Weiss law even at relatively high temperatures

Adolescent deviation and age

Traditional theories of delinquency causation generally fail to consider delinquency in the context of norms and age-role transitions peculiar to adolescence. Hence, in this study, an age-based theory of delinquency causation is developed, which assumes the importance of norms and roles specific to adolescence. This theory draws upon the assumption that socialization is recurrent, in contrast to the premises regarding socialization which underlie traditional theories of adolescent deviance. The recurrent model of socialization and that assumed by traditional theorists are discussed, and their implications for the causes of delinquent behavior are examined. Some effort is made to show that the recurrent model of socialization suggests an anomie of age as the basis for delinquent acts. It is suggested that this age-based anomie stems from conditions of normlessness associated with certain role transitions in adolescence and the pacing of these transitions. Further, it is suggested that certain groups are especially prone to an anomic age transition. The role transitions most likely to be subject to such anomic conditions and the adolescent subgroups most prone to experience anomie as a result of the pacing of their age-role transitions are identified .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45260/1/10964_2005_Article_BF01537174.pd

Metamagnetic Behavior of Linear Chain Pyridine Compounds: Co(Pyridine)₂Cl₂, Fe(Pyridine)₂Cl₂, Fe(Pyridine)₂(NCS)₂ and Ni(Pyridine)₂Cl₂

Magnetic phase transitions in the pyridine (pyr) compounds Co(pyr)2Cl2, Fe(pyr)2Cl2, Fe(pyr)2(NCS)2 and Ni(pyr)2Cl2 have been observed at applied magnetic fields of ~0.7, 0.7, 1.1 and 2.7 kG respectively. These low field phase transitions are observed in the Fe and Ni compounds at T = 4.2 K, and in the Co compound at T \u3c 3K, and are consistent with metamagnetic behavior. Magnetic saturation is not achieved in any of these compounds for fields of 60 kG, reflecting high anisotropy

Sweep Rate Effects and Magnetization Loops of Both High- and Low-Temperature Superconductors

We present an extensive study of the magnetization properties of high quality YBa2Cu3O7 and conventional low-temperature superconducting single crystals using a vibrating sample magnetometer. The experimental conditions cover a wide range of temperatures, applied fields (up to 30 T), and sweep rates. The experimentally measured linear relationship between the magnetization and the logarithm of the sweep rate is examined in detail. A simple picture of vortex motion as a combination of drift and diffusion components provides a particularly useful model for analyzing the experimental results

High-Field Magnetization Scaling Relations for Pure and Ni-Substituted Single-Crystal YBa2Cu3O7

Several scaling relations are inferred from magnetization data taken in fields up to 20 T on single crystal YBa2Cu3-xNixO7 where 0≤x≤0.03. A Bean-like critical state exists in the samples at high fields (20 T) and low temperatures (4.2 K) regardless of x. Strong systematics are also displayed in the temperature dependent data: it is found that beyond an applied field breakpoint, which itself scales with temperature as (1-T/Tc)3/2, all the scaled hysteresis loops decrease in a universal manner. This universal behavior of the normalized magnetization is well described as a hyperbolic function of the normalized applied field. A quantitative study of the dependence of the measured magnetization as a function of the sweep rate of the applied field is also presented. The measured magnetization is found to depend logarithmically on the sweep rate. The simplest diffusion models are inadequate to explain the data

Resistive Transitions of Ni-Doped Ba2YCu3O7 in High-Magnetic Fields

Resistive transitions of single crystal Ba2YCu3-χNiχO7 were studied in magnetic field up to 20 tesla. For dop concentrations of χ = 0.01 and χ 0.03, the transition temperature in zero field decreased from the undoped value of 88K to 82K and 76K respectively, while the transition width †T (10%-90%) is still less than 1K. Moreover, Ni-doping has a dramatic effect on the resistive transition, tending to suppress the field dependent broadening