Bismuth Telluride Nano-Coolers for Magnetic Sensors

Mannam, Raja; Kola, Avinash; Agarwal, Mangilal; Singh, Varshini; Roy, Amitava; Young, David; Varahramyan, Kody; Davis, Daniel Cochece

doi:10.1149/1.3005193

Cited by 3 publications

(3 citation statements)

References 8 publications

(11 reference statements)

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“…The thermoelectric phenomenon involves the conversion between electrical and thermal energies, and it is widely used in refrigeration and electric generation. Various applications include refrigeration for microelectronic, 1,2 optoelectronic, 3 and chargecoupled devices, magnetic sensors, 4 generation of electric energy for space, 5 and commercial applications ͑waste heat recovery in automobiles and industries͒. The nondimensional figure of merit ZT ͓ZT = S 2 T/k͔ characterizes thermoelectric materials and shows the relationship between the Seebeck coefficient ͑S͒, the electrical conductivity ͑͒, the thermal conductivity ͑k͒, and the absolute temperature ͑T͒.…”

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confidence: 99%

Electrodeposition and Thermoelectric Characterization of Bismuth Telluride Nanowires

Mannam

Agarwal

Roy

et al. 2009

J. Electrochem. Soc.

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Bismuth telluride (BixTey) nanowires were electrodeposited from aqueous acidic solutions containing different Bi3+/HTeO2+ (20/20 and 20/10 mM) concentration ratios. The polarization plots predicted that combined solutions exhibit more noble reduction potentials than individual solutions. Optimized deposition potentials were obtained from the combined electrolyte polarization plots. An anomalous codeposition behavior caused an increase in Te concentration for depositions in the kinetic region of bismuth telluride; otherwise, decreasing Te concentrations with increased deposition potentials was observed from a composition analysis. X-ray diffraction showed a dominant (110) orientation for nanowires at low deposition potentials. n-Type nanowires were obtained from both electrolytes, while p-type nanowires were only obtained from the 20/10 electrolyte for low Te (<30%) concentrations. An intrinsic to extrinsic transition was observed for nanowires deposited from the 20/10 electrolyte. The highest measured Seebeck coefficient was −318.7 and 117μV/K for n- and p-type nanowires, respectively. The Seebeck coefficient dependence on the resistivity and composition of the nanowires is discussed.

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confidence: 99%

Electrodeposition and Thermoelectric Characterization of Bismuth Telluride Nanowires

Mannam

Agarwal

Roy

et al. 2009

J. Electrochem. Soc.

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“…High thermal conducting dielectric caps were tested to provide a quicker heat dissipation path (7). A novel in situ thermoelectric cooling of GMR magnetic sensor, using Bi x Te y caps, was proposed in our earlier report (8). Bi x Te y is the alloy of choice for thermoelectric cooling because of its high figure of merit at room temperature (9).…”

Section: Introductionmentioning

confidence: 99%

Novel Thermoelectric Cooling of Magnetic Sensors

et al. 2009

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In situ thermoelectric cooling of GMR nanowires is a novel method to obtain reliable and more sensitive GMR devices. Bismuth telluride (BixTey) caps were used to provide localized thermoelectric cooling of GMR nanowires. BixTey nanowires were electrodeposited from aqueous acidic solutions containing different Bi3+ and HTeO2+ concentrations. GMR layered structures were electrodeposited from a Co-rich electrolyte using a pulsed potential technique. The highest Seebeck coefficients of -318.7 µV/K and 117 µV/K were measured for n-type and p-type nanowires, respectively. P-type nanowires were obtained for low Te concentrations (<30%). Initial experiments were conducted to study the effect of thermoelectric cooling on sensitivity of GMR nanowires. Results showed that using BixTey caps can improve magnetic sensitivity of GMR nanowires.

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“…[4][5][6] A novel in situ thermoelectric cooling of GMR magnetic sensor, using Bi x Te y caps, was proposed in our earlier report. 7 Mannam et al predicted that the addition of Bi x Te y thermoelectric caps can help heat dissipation, maintaining the GMR sensor at constant temperature.…”

Section: Introductionmentioning

confidence: 99%