This study addresses challenges in conventional threeaxis force sensors—namely the coupling between shear and normal forces, insufficient flexibility, and complex decoupling algorithms—which limit their application in precision teleoperation of robots. To overcome these issues, we propose a three-dimensional magnetic tactile sensor based on a single-layer annular sinusoidal magnetic film that enables real-time, self-decoupled measurement of tri-axial forces. Through the single-layer magnetic film structure, the sensor achieves self-decoupling of three-dimensional force, thereby avoiding multi-dimensional force coupling and the dependence on complex algorithms. Calibration experiments demonstrate that the sensor exhibits excellent performance with high sensitivity and high accuracy. Along the Z-axis, the measurable range is 0～15 N with a sensitivity of 0.014 7 kPa-1 and a root-mean-square error of 0.001 5 mT. Along the X- and Y-axes, the measurement range is -5 to 5 N, with sensitivities of 0.020 3 and 0.020 9 kPa-1, and RMSEs of 0.002 and 0.001 9, respectively. The sensor body adopts a flexible structural design, featuring low power consumption and a high output frequency. In slip-control experiments, a slip-control strategy was implemented on the end effector of the robotic arm. By mounting the designed tactile sensor on an augmented-intelligence gripper, the system monitors the normal and tangential contact forces in real time and, together with an incremental PID controller, rapidly adjusts the gripping force upon slip detection to stably grasp a container with a dynamically increasing load. The average response time is 113.3 ms, demonstrating the stability and reliability of the proposed slip-control strategy in practical applications.