Nanocasting synthesis of mesoporous SnO₂ with a tunable ferromagnetic response through Ni loading

Abstract

Ni-doped SnO2 mesoporous powders exhibit ferromagnetism at low and room temperatures, which can be tuned by adjusting the Ni loading.

Unraveling the Origin of Magnetism in Mesoporous Cu-Doped SnO2 Magnetic Semiconductors

“…Conversely, for the sample with 1 at.% Cu, the binding energy of Cu 2p 3/2 is 932.9 eV, a slightly lower value, which falls in an energy range characteristic of mixed Cu valence states (i.e., Cu 1+ and Cu 2+ ) [ 48 , 49 ] and, thus, representing a mixture of Cu 2 O and CuO. Furthermore, partial non-stoichiometry is likely to be caused by oxygen vacancies associated with the synthesis method [ 50 , 51 ], as also evidenced in mesoporous transition metal-doped In 2 O 3 and Ni-doped SnO 2 [ 18 , 19 ].…”

“…Most oxide DMSs reported so far have been prepared as continuous thin films, bulk materials, or coarse polycrystalline powders. Although there are a few studies on the growth of oxide DMS nanoparticles [ 16 ] and nanowires [ 17 ], the synthesis of three-dimensional (3D) mesoporous oxide DMS structures by hard-templating has been just recently reported [ 18 , 19 ]. Engineering 3D magnetic semiconductor architectures with ordered arrangements (i.e., controlled size, shape, and orientation of the pores and pore walls) is highly desirable since this allows for the precise tuning of the physicochemical properties [ 20 ].…”

Evaporation-induced self-assembly synthesis of Ni-doped mesoporous SnO2 thin films with tunable room temperature magnetic properties

“…Conversely, the small ferromagnetic response could be ascribed to the combined effect from the doping TM and the presence of oxygen vacancies, in agreement with previous works on undoped SnO 2 films, 53 TM-doped dense oxide semiconductor films 54,55 and TM-doped InO 2 35,36 and SnO 2 mesoporous powders. 37 Actually, a mechanism based on ferromagnetic exchange interactions mediated by shallow donor electrons trapped in oxygen vacancies was proposed to account for room-temperature ferromagnetism in dilute ferromagnetic oxides and nitrides. 55 Ab-initio energy-band calculations showed later that the donor impurities mainly consisted of hybridized 3d-4s TM-cation electronic states.…”

“…It is surprising that although many of the cutting-edge technological applications in magnetism and spintronics also rely on surface or interface magnetic phenomena, the use of nanoporous magnetic frameworks in these technologically-relevant fields has just emerged during the last few years. [33][34][35][36][37][38] During the last few years, we have reported the synthesis and magnetic characterization of TM-doped oxide semiconducting mesoporous powders prepared by nanocasting. [35][36][37] The doping with the TM confers a magnetic character to this type of materials, which can then be categorized as mesoporous oxide-diluted magnetic semiconductors (MODMS).…”

“…[33][34][35][36][37][38] During the last few years, we have reported the synthesis and magnetic characterization of TM-doped oxide semiconducting mesoporous powders prepared by nanocasting. [35][36][37] The doping with the TM confers a magnetic character to this type of materials, which can then be categorized as mesoporous oxide-diluted magnetic semiconductors (MODMS). These mesoporous frameworks may be appealing for spintronic applications, where the spin of the electrons (and not only the electric charge) can be used for the processing of information.…”