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Magnetization reversal phenomena (MRP) along magnetic order-order transitions are reported on impurity-doped magnetic systems. The magnetization of (Cr0.70Ti0.30)5S6 are investigated on heating and cooling runs in various magnetic fields, as a typical order-order transition is known to occur on Cr5S6 at a transition temperature T(sub t).

Magnetization reversal phenomena (MRP) along magnetic order-order transitions have recently been reported on impurity-doped magnetic systems. Because imperfect long-range magnetic order exists in these systems, it is expected that a systematic investigation of MRP will give physical information on thermomagnetic processes of magnetic systems in the range from the micro- to nanoscales. As a typical order-order transition (a state doubly modulated by helical and canting orders to a collinear ferrimagnetic state) has been known to occur on Cr5S6 at a transition temperature Tt, we investigate the magnetizations of (Cr0.70Ti0.30)5S6 on heating and cooling runs in various magnetic fields. At 20 Oe, the field-cooled magnetization just below the Curie temperature has a positive sign; the sign turns negative below the compensation temperature TCM (first step) and finally returns to positive below Tt (second step). The first-step MRP observed in this system is explained by the potential barriers resulting from anisotropy energy when the preferred direction of collinear ferrimagnetic moment reverses. The proposed mechanism for second-step MRP is the pinning effect caused by the impurity atoms (Ti) in the helical long-range-order chains. Comparing other examples of MRPs, we discuss the roles of local impurity centers in the thermomagnetic process in magnetic order-order transitions. [ABSTRACT FROM AUTHOR]

Magnetization reversal phenomena (MRP) along magnetic order-order transitions have recently been reported on impurity-doped magnetic systems. Because imperfect long-range magnetic order exists in these systems, it is expected that a systematic investigation of MRP will give physical information on thermomagnetic processes of magnetic systems in the range from the micro- to nanoscales. As a typical order-order transition (a state doubly modulated by helical and canting orders to a collinear ferrimagnetic state) has been known to occur on Cr5S6 at a transition temperature Tt, we investigate the magnetizations of (Cr0.70Ti0.30)5S6 on heating and cooling runs in various magnetic fields. At 20 Oe, the field-cooled magnetization just below the Curie temperature has a positive sign; the sign turns negative below the compensation temperature TCM (first step) and finally returns to positive below Tt (second step). The first-step MRP observed in this system is explained by the potential barriers resulting from anisotropy energy when the preferred direction of collinear ferrimagnetic moment reverses. The proposed mechanism for second-step MRP is the pinning effect caused by the impurity atoms (Ti) in the helical long-range-order chains. Comparing other examples of MRPs, we discuss the roles of local impurity centers in the thermomagnetic process in magnetic order-order transitions. [ABSTRACT FROM AUTHOR]

We have observed the lasing of submicron-sized ZnO particle in a Fabry-Perot cavity at low temperatures. A thin alkali-halide crystal including a small amount of ZnO particles are sandwiched between two quartz plates arranged as a pair of opposite mirrors, that is, a Fabry-Perot cavity. Under low excitation due to a He–Cd laser, emissions of free and bound excitons and their phonon replicas are recognized markedly, while a biexciton emission band appears under high-dense excitation by a pulsed N2 laser. Biexciton lasing is demonstrated as a narrowed emission by focusing the excitation light beam on an appropriate position being a ZnO particle in the cavity. When a cavity length satisfies the resonant condition, the lasing occurs in the spectral region of the biexciton emission band and with the very small divergence angle. The obtained threshold of excitation-power density is about 0.50 MW/cm2. We discuss lasing in terms of stimulated emission caused by population inversion between biexciton and exciton states. [ABSTRACT FROM AUTHOR]

Examines the mechanism of electrochromism for amorphous WO[sub3] thin films. Deposition of the WO[sub3] film; Morphology and crystal structure of the WO[sub3] film; Diagram of electrochromic cell used for the coloration.