Nanoscopic transformations and GMR in bulk non-equilibrium Cu–Co alloys

Ribbons and micro-wires of CuCo segregated alloys

“…This range of compositions is in the region of the phase diagram [6] of the Cu-Co alloys that induce spinodal decomposition, while it also shows a large GMR, as we have clearly demonstrated [5]. The magneto-transport results in the ribbons, including resistivity, magnetization and GMR, exhibit a noticeable change with thermal annealing.…”

“…In order to relate GMR behavior to the nanostructures, we have extensively studied [3][4][5] the properties of bulk immiscible Cu ð100ÀxÞ Co x ribbons, for 5pxp35 in the last years. This range of compositions is in the region of the phase diagram [6] of the Cu-Co alloys that induce spinodal decomposition, while it also shows a large GMR, as we have clearly demonstrated [5].…”

Spinodal decomposition and giant magnetoresistance

“…To relate the GMR and structure, in previous articles we have studied the behavior of Cu (100Àx) Co x ribbons, with x ¼ 5, 10, 15 and 20 [6,8,9]. This range of compositions is in the region of the phase diagram [10] that favors the appearance of spinodal decomposition, and also shows large GMR [9].…”

Magnetic, resistive and magnetoresistive properties of melt spun CoCu alloys

“…Recently [5,6], such a microstructure has also been detected in as spun specimens, suggesting that the optimal structure could be obtained directly in the as cast condition, without any further heat treatment, by tunning the cooling rate. In this sense, the symmetric solidification conditions imposed by the twin roller configuration becomes attractive.…”

“…In these heterostructures Co is reported to be in two main structural components with distinctly different properties [4][5][6]. A magnetically stiff component consisting of small Co agglomerates with an average blocking temperature between 150 and 200 K. The second structural component consists of CoCu alloyed grains with large, spinodal-like concentration fluctuations; thermoremanence studies indicate that this phase has an average blocking temperature of about 35 K [4].…”