Highly Flexible and Twistable Freestanding Single Crystalline Magnetite Film with Robust Magnetism

Abstract

Magnetic materials and devices that can be folded and twisted without sacrificing their functional properties are highly desirable for flexible electronic applications in wearable products and implantable systems. In this work, a high‐quality single crystalline freestanding Fe3O4 thin film with strong magnetism has been synthesized by pulsed laser deposition using a water‐dissolvable Sr3Al2O6 sacrificial layer, and the resulting freestanding film, with magnetism confirmed at multiple length scales, is highly flexible with a bending radius as small as 7.18 µm and twist angle as large as 122°, in sharp contrast with bulk magnetite that is quite brittle. When transferred to a polydimethylsiloxane support layer, the Fe3O4 film can be bent with large deformation without affecting its magnetization, demonstrating its robust magnetism. The work thus offers a viable solution for flexible magnetic materials that can be utilized in a range of applications.

Probing Ultrafast Dynamics of Ferroelectrics by Time‐Resolved Pump‐Probe Spectroscopy

“…[108] This results indicate that the magnetic domains are not aligned in one of the three equivalent allowed antiferromagnetic cycloid directions. In a (001) pc -oriented BFO single crystal, the absorption of Ψ 1 (2) and Ψ 1 (1) only appears at the THz polarization along the[1 10] pc axis, and the polarization dependence does not change even after annealing the sample at a temperature above the Neel point (right panel in Figure 9b). This selection rules are similar to the E-mode phonons of BFO, which illustrate that the magnonphonon coupling (a coupling between magnetic and lattice excitations) is strong enough to govern the polarization dependence of magnon absorptions.…”

“…Nowadays,microelectronic devices are widely applied in various fields, and the demands for higher transmission speed, multifunctional and artificial intelligent devices are substantially increased. [ 1 , 2 , 3 , 4 ] With the great desire for high‐speed, miniature, and intelligent functional materials, [ 5 , 6 ] the “smart” ferroelectric offering distinct advantages of rapid response speed, non‐volatility, and low power consumption has garnered significant researches. [ 7 , 8 , 9 , 10 , 11 , 12 ] Ferroelectric is a certain type of material that exhibits spontaneous asymmetric crystal structure with permanent electric dipole moments [ 7 , 13 ] ( Figure 1 a ), and the spontaneous polarization possesses at least two energetically degenerate crystallographic directions.…”

Perpendicularly magnetized Co/Pd-based magneto-resistive heterostructures on flexible substrates

“…2) and nowadays showing all their outstanding potentialities in many technological elds including energy, optics, sensors and information storage, among others. [3][4][5][6][7][8][9][10][11][12][13] Aiming to widen the domain of exible electronics, a signicant effort has been recently pursued to develop spin-related electronic devices with in-plane magnetic anisotropy on exible substrates. 3,5,[14][15][16][17][18][19][20][21][22][23][24] With respect to conventional electronics, spintronic devices exploit electron spin to achieve additional functionality not provided by charge transport.…”

Highly Flexible Freestanding BaTiO3‐CoFe2O4 Heteroepitaxial Nanostructure Self‐Assembled with Room‐Temperature Multiferroicity

“…In recent years, water-soluble Sr 3 Al 2 O 6 (SAO) [21] and Ba 3 Al 2 O 6 [22] have emerged as a powerful solution for fabricating freestanding oxide films, and a great variety of freestanding structures have been demonstrated, including ferroelectric BiFeO 3 , [23] PbTiO 3 , [24] and BaTiO 3 (BTO), [25] as well as magnetic La 0.7 Ca 0.3 MnO 3 , [22] La 0.67 Sr 0.33 MnO 3 , [26] and Fe 3 O 4 . [27] These freestanding structures are fully relieved from substrate constraint and thus enjoy great flexibility, and they provide an alternative strategy to realize flexible electronics that is not limited by a flexible substrate. Nevertheless, freestanding heterostructures, which are usually necessary for multiple functionalities, remain rare due to difficulties in processing except for a bilayered BTO/Fe system.…”