Systematically study on the magnetism and critical behaviour of layered NdMn1.4Cu0.6Si2

Abstract

The strong dependence of the field-induced on the body-centered tetragonal ThCr2Si2-type and the critical behaviour of magnetic phase transition in NdMn2-xCuxSi2based compounds guide us to study the substitution Mn (atomic radius = 1.35 Å) by Cu (atomic radius = 1.28 Å) in layered NdMn1.4Cu0.6Si2compound. Room temperature x-ray diffraction study indicates clearly that most of the reflections can be identified with ThCr2Si2-type structure with space group I4/mmm. It found lattice parameters a slightly increases and lattice parameter c decrease compare to NdMn2Si2as indicated the decreasing of volume structure. The Neel temperature TNis found at 340 K while Curie temperature TCfound at 75 K respectively. The increasing concentration of Cu in replacement of Mn changes the magnetic phase transition from first order type for NdMn2Si2to second order type for layered NdMn1.4Cu0.6Si2compound as been determined by particular the S-shaped nature of the Arrott plot near TC. Our results indicate that the magnetic-field-induced magnetic phase transition plays a critical role on producing large magnetocaloric effect in these systems especially on second order type as the key for further investigation. The critical behaviour analysis in the vicinity of TCdemonstrates that the magnetism of the layered NdMn1.4Cu0.6Si2compound is governed by long range interactions.

Structural Analysis of Bulkhead Patch Repair Due to Heat Damage

“…For example, when subjected to heat for a long period, creep always increase with temperature increases. Stages of creep can be divided into three developments [10][11]; primary creep, which happens at a fast rate, secondary creep, which occurs at a steady pace and tertiary creep happens rapidly and rupture to failure. The author also mentioned that the creep generally happened at 30% to 40% of the materials melting temperature.…”

“…The outcome of the simulation does not directly show the strength of the affected structure. The resultant strength can be defined using an experiment by estimation from the graph of the effect of exposure at the elevated temperature [11]. The graph in Fig.…”

INVESTIGATION ON PURITY AND THERMAL STABILITY OF Ag2O RAW MATERIAL USED TO SYNTHESIS Ag2Nb4O11 CERAMICS USING THERMAL AND PHASE ANALYSIS METHOD

“…The change from black brownish to grey colour indicates that the oxide is in the middle decomposition process before finally turned to whitish metallic of Ag metal. In this study, the instability of Ag2O (99% pure, Sigma Aldrich) raw material may responsible to the failure in synthesizing phase pure Ag2Nb4O11 ceramics; content inspection of a raw material and its purity are essential prior using it [9][10].…”