13. Magnetoresistance (MR) ratio is defined as the ratio of the change in resistivity (due to change in configuration of electrons from antiparallel to parallel) to the resistivity in parallel configuration of electrons.
14. MR is due to spin of electrons and was first observed in ferromagnetic materials as AMR (Anisotropic Magnetoresistance).
24. Piraux et al. was first to study GMR in electrodeposited multilayered nanowires. They observed around 15% GMR at room temperature in Co/Cu layers. [5]
25. Blondel et al. observed GMR of 14% for Co/Cu and 10% for FeNi/Cu multilayered nanowires. [6]
26. Liu et al. investigated Co/Cu multilayerand observed GMR of 11% at room temperature and 22% at 5K . [7]
27. CoFeCu/Cu multilayered nanowires were studied by Seyama et al. and observed CPPGMR was twice that of CIP GMR on thin film for the same elements.[8]
28.
29. Blondel et al. studied CoNi/Cu multilayered nanowires by pulsed potential technique and observed 20% GMR at room temperature with same ferromagnetic and nonmagnetic layer thickness. [10]
30. Schwarzacher et al. and Heydon et al. investigated CoNiCu/Cu in polycarbonate membranes and observed 22% GMR at room temperature. The reduction in the dissolution of Co was observed in the deposition of Cu with the addition of Ni.[11]
31. Evans et al. reported 55% GMR at room temperature and 115% GMR at low temperature on AAO with CoNiCu/Cu multilayers. They also reported that better GMR was observed with AAO template than with PC membranes. [12]
33. Huang and Podlaha investigated quaternary system of FeCoNiCu and observed 4% GMR at 300K and 18% at 4K with a Cu layer thickness of 1.8nm. Anodic dissolution during multilayer deposition at low potential pulse was observed and galvanostatic triple pulses with relaxation period were introduced to reduce it. [13]
34.
35. Dolati et al. studied FeCrNiMo alloys using chloride electrolyte and reported increase in Cr content increased the current density. They also observed fine-grain, smooth and compact deposits of FeCrNiMo. [15]
36. Xin-Quai et al. investigated pulse electrodeposition of Cr from trivalent bath and reported that thicker coatings and finer grains were observed with lower temperature and current density. [16 ]
37. Lallemandet al. studied electrodeposition of soft CoFeCr films and reported that the addition of Cr increases the resistivity of the alloy. [17]
38. Ericksson et al. investigated the effect of addition of chromium in FeNi alloy. They observed the improvement in crystal anisotropy with improved texture and small grain size that resulted in the decrease of saturation magnetization. [18]
64. Beside alloy potential time all other parameters were kept constant.
65.
66.
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68.
69.
70.
71.
72.
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74. Cu pulsing time was kept for 100secs and alloy pulsing time for 20secs.
75. 20nm pore size AAO and 200nm pore size PC were used as substrate.
76. Dichloromethane was used for dissolving membrane and liberating nanowires in case of PC template.
77.
78.
79.
80. Highest GMR was observed at -2.2V, 1sec and 2500 layers.
81.
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84.
85. Increase in number of bilayers increased GMR percentage with highest GMR obtained as 14.56% for FeCoNiCu/Cu and 5.82% for CrFeCoNiCu/Cu nanowires at 2500 layers.
86. Highest GMR curves tended to saturate faster which is desirable for read sensors.
87. Addition of Cr on the alloy region tended to decrease the GMR because Cr being non magnetic and its presence in ferromagnetic region deteriorated interlayer exchange coupling phenomena.