fig2

Figure 2. Soft electronics based on magnetic nanomembranes/nanostructures. (A) Schematic illustration of the structure and mechanism of a simplified trilayer GMR sensor; (B) An imperceptible magnetic sensor foil consisted of GMR sensors. Top frame: structure of the sensor. Middle frame: optical image of a sample (marked by the blue dashed rectangle) mounted to a stretching stage. Bottom frames: scanning electron microscopy (SEM) images of the sample under 50% compressive strain. The red arrow indicates the direction of the applied magnetic field. Reproduced with permission from Ref.^[77]. Copyright^© 2015. Springer Nature; (C) An SCMN with eight functions. Left frame: schematic illustration (temp.: temperature). Right frames: optical images of the SCMN attached to a sheet of paper, integrated on a human finger and human skin, and stretched manually. Reproduced with permission from Ref.^[78]. Copyright^© 2018. Springer Nature; (D) Schematic illustration of the structure and mechanism of an AMR sensor; (E) An e-skin compass. Left frame: structure of the device. Right frames: optical micrography of the e-skin compass. Reproduced with permission from Ref.^[41]. Copyright^© 2018. Springer Nature; (F) An active matrix consisting of micro-origami sensor arrays. Left frame: structure of the device. Inset of the left frame shows the micrograph of the AMR sensors. Right frame: optical image of an integrated micro-origami magnetic sensor device with 8 × 8 pixels. Right frame: magnified view of several pixels. Reproduced with permission from Ref.^[87]. Copyright^© 2022. Springer Nature; (G) Schematic illustration of the structure and mechanism of a TMR sensor; (H) A flexible TMR sensor. Top frames: transmission electron microscopy (TEM) images of the MTJ structure. Bottom frame: optical image of MTJs transferred onto nitrile glove. Reproduced with permission from Ref.^[104]. Copyright^© 2016. John Wiley and Sons; (I) A film-type strain gauge with the exchange-biased MTJ. Left frame: schematic illustration of the device. Top right frame: optical image of the motor-driven tensile machine for the sample. Bottom right frame: illustration of structure. Reproduced with permission from Ref.^[107]. Copyright^© 2022. AIP Publishing. AFM: Antiferromagnetic; AMR: anisotropic magnetoresistance; GMR: giant magnetoresistance; MTJs: magnetic tunneling junctions; PET: polyethylene terephthalate; SCMN: stretchable and conformable matrix network; TMR: tunneling magnetoresistance.