Thermal spin transport and energy conversion

Vandaele, Koen; Watzman, Sarah J.; Flebus, Benedetta; Prakash, Arati; Zheng, Yuanhua; Boona, Stephen R.; Heremans, Joseph P.

doi:10.1016/j.mtphys.2017.05.003

Cited by 62 publications

(33 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the PF values obtained are similar an even larger than to that of widely used thermoelectric material bismuth-telluride (in the range 1–6 mW/K

m) and at least one order of magnitude larger than the ones reported for flexible thermoelectric films based on optimized conducting polymers [ 34 , 35 ]. Large RT value of PF of about 11.0 mW/K

m have been obtained in interconnected Co NWs, which is almost as good as the bulk Co that display the largest PF value of about 15 mW/K

m [ 36 ]. Moreover, regarding p-type materials, the RT PF estimated for the Fe and Ni

NW networks are close to the largest PF at RT of about 9 mW/K

m found for CePd

[ 37 , 38 ].…”

Section: Results and Discussionmentioning

confidence: 99%

Spin Caloritronics in 3D Interconnected Nanowire Networks

et al. 2020

View full text Add to dashboard Cite

Recently, interconnected nanowire networks have been found suitable as flexible macroscopic spin caloritronic devices. The 3D nanowire networks are fabricated by direct electrodeposition in track-etched polymer templates with crossed nano-channels. This technique allows the fabrication of crossed nanowires consisting of both homogeneous ferromagnetic metals and multilayer stack with successive layers of ferromagnetic and non-magnetic metals, with controlled morphology and material composition. The networks exhibit extremely high, magnetically modulated thermoelectric power factors. Moreover, large spin-dependent Seebeck coefficients were directly extracted from experimental measurements on multilayer nanowire networks. This work provides a simple and cost-effective way to fabricate large-scale flexible and shapeable thermoelectric devices exploiting the spin degree of freedom.

show abstract

“…However, the PF values obtained are similar an even larger than to that of widely used thermoelectric material bismuth-telluride (in the range 1–6 mW/K

m) and at least one order of magnitude larger than the ones reported for flexible thermoelectric films based on optimized conducting polymers [ 34 , 35 ]. Large RT value of PF of about 11.0 mW/K

m have been obtained in interconnected Co NWs, which is almost as good as the bulk Co that display the largest PF value of about 15 mW/K

m [ 36 ]. Moreover, regarding p-type materials, the RT PF estimated for the Fe and Ni

NW networks are close to the largest PF at RT of about 9 mW/K

m found for CePd

[ 37 , 38 ].…”

Section: Results and Discussionmentioning

confidence: 99%

Spin Caloritronics in 3D Interconnected Nanowire Networks

et al. 2020

View full text Add to dashboard Cite

show abstract

“…From the theoretical study based on the spin-motive force, the magnon drag thermopower is described asSmag∝false(normalβ−3normalαfalse)Psκmwhere β, α, P s , and κ m indicate the spin-transfer torque parameter, the Gilbert damping parameter, the spin polarization of conduction electrons, and the thermal conductivity due to magnons, respectively ( 9 , 10 , 32 ). It was pointed out that the ratio β/α is equal to S t / S i , which is the ratio of the total magnetic moment ( S t ) to the spin moment of itinerant electrons ( S i ) ( 9 , 34 ). While conventional ferromagnets such as Fe belong to itinerant electron systems, they are close to localized moment systems in the Rhodes-Wohlfarth plot (fig.…”

Section: Discussionmentioning

confidence: 99%

Observation of enhanced thermopower due to spin fluctuation in weak itinerant ferromagnet

et al. 2019

View full text Add to dashboard Cite

show abstract

“…These multilayers are easier to fabricate by potentiostatic electrochemical deposition than CoNi/Cu. Also, cobalt exhibits the largest thermoelectric power factor (PF = S 2 σ ≈ 15 mW K −2 m −1 for bulk material with σ the electrical conductivity) at RT . The power factor is the physical parameter that relates to the output power density of a thermolectric material.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Control of Flexible Thermoelectric Devices Based on Macroscopic 3D Interconnected Nanowire Networks

Araujo

Gomes

Piraux

2019

Adv Elect Materials

View full text Add to dashboard Cite

of reproducibility in the experiments has limited the application as heat harvesters. Although there have been some initial studies on the thermoelectric analogues of giant magnetoresistance (GMR) in magnetic multilayers with current inplane configuration, [9][10][11][12] the effects of interfaces make the interpretation of the results more delicate than in the simpler current-perpendicular-to-plane (CPP) configuration. [13] Indeed, in the limit of no-spin relaxation, most of the CPP-GMR data can be understood using a simple two-current series-resistor model, in which the resistance of layers and interfaces simply add and where "up" and "down" charge carriers are propagating independently in two spin channels with large spin asymmetries of the electron's scattering. [14,15] Similarly, the spin-dependent thermoelectric effects exploit the fact that the Seebeck coefficients for spin-up and spin-down electrons are also different. The diffusion thermopower arises from the diffusion of charge carriers opposite to the temperature gradient. It is related to the energy dependent conductivity of the material σ(ε ) by Mott's formulawith L 0 = 2.44 · 10 −8 V 2 K −2 the Lorenz number and e the electron charge (positive). According to Einstein's relation for a metal or alloy with isotropic properties, the conductivity is proportional to the density of states N(ε ) and to the scattering time τ(ε ), where both terms in Equation (1) are to be evaluated at the Fermi level ϵ F . Because of the pronounced structure of the d-band and the high energy derivative of the density of states at the Fermi level in 3D ferromagnetic metals, large diffusion thermopowers are obtained (e.g., S ≈ −30 µV K −1 in cobalt at room temperature (RT)). Moreover, significantly different Seebeck coefficients for spin-up and spin-down electrons, S ↑ and S ↓ , are expected because the d-band is exchange split in these ferromagnets, as suggested from previous works performed on dilute magnetic alloys. [16,17] To date, most of the investigations of thermoelectric transport in CPP-GMR systems were performed on lithographically defined nanopillars, single nanowire (NW), and parallel Spin-related effects in thermoelectricity can be used to design more efficient refrigerators and offer promising applications for the harvesting of thermal energy. The key challenge is to design structural and compositional magnetic material systems with sufficiently high efficiency and power output for transforming thermal energy into electric energy and vice versa. The fabrication of large-area 3D interconnected Co/Cu nanowire networks is demonstrated, thereby enabling the controlled Peltier cooling of macroscopic electronic components with an external magnetic field. The flexible, macroscopic devices overcome the inherent limitations of nanoscale magnetic structures that are caused by insufficient power generation capability limiting the heat management applications. From properly designed experiments, large spin-dependent Seebeck and Peltier coefficients of −9.4 µV K −1 and −2.8 ...

show abstract

Thermal spin transport and energy conversion

Cited by 62 publications

References 42 publications

Spin Caloritronics in 3D Interconnected Nanowire Networks

Spin Caloritronics in 3D Interconnected Nanowire Networks

Observation of enhanced thermopower due to spin fluctuation in weak itinerant ferromagnet

Magnetic Control of Flexible Thermoelectric Devices Based on Macroscopic 3D Interconnected Nanowire Networks

Contact Info

Product

Resources

About