Topologically nontrivial spin textures have recently been investigated for spintronic applications. Here, we report on an ultrathin magnetic film in which individual skyrmions can be written and deleted in a controlled fashion with local spin-polarized currents from a scanning tunneling microscope. An external magnetic field is used to tune the energy landscape, and the temperature is adjusted to prevent thermally activated switching between topologically distinct states. Switching rate and direction can then be controlled by the parameters used for current injection. The creation and annihilation of individual magnetic skyrmions demonstrates the potential for topological charge in future information-storage concepts.

Vector spin chirality is one of the fundamental characteristics of complex magnets. For a one-dimensional spin-spiral state it can be interpreted as the handedness, or rotational sense of the spiral. Here, using spin-polarized scanning tunneling microscopy, we demonstrate the occurrence of an atomic-scale spin spiral in finite individual bi-atomic Fe chains on the (5×1)-Ir(001) surface. We show that the broken inversion symmetry at the surface promotes one direction of the vector spin chirality, leading to a unique rotational sense of the spiral in all chains. Correspondingly, changes in the spin direction of one chain end can be probed tens of nanometers away, suggesting a new way of transmitting information about the state of magnetic objects on the nanoscale.

As the characteristic length scale of devices continues to decrease, it is essential to understand the fundamental magnetic properties of reduced dimension structures. This paper examines the electronic and magnetic properties of two-dimensional nanoscale Co islands on an Ir(111) surface using spin-polarized scanning tunneling microscopy. The pseudomorphic Co islands investigated are ferromagnetic and single domain, with the magnetic easy axis normal to the sample surface. Remarkably, the coercivity of these islands is greater than 4 T and magnetic saturation of the islands requires an applied field of at least 5 T.

We demonstrate a canted magnetization of biatomic zigzag Co chains grown on the (5 × 1) reconstructed Ir(001) surface using density functional theory (DFT) calculations and spin-polarized scanning tunneling microscopy (SP-STM) experiments. It is observed by STM that biatomic Co chains grow in three different structural configurations. Our DFT calculations show that they are all in a ferromagnetic (FM) state. Two chain types possess high symmetry due to two equivalent atomic strands and an easy magnetization direction that is along one of the principal crystallographic axes. The easy magnetization axis of the zigzag Co chains is canted away from the surface normal by an angle of 33°. This giant effect is caused by the broken chain symmetry on the substrate in combination with the strong spin-orbit coupling of Ir. SP-STM measurements confirm the stable FM order of the zigzag chains with a canted magnetization.