 The study demonstrates the ability to control antiferromagnetic order in MN2AU-thin films using phase-locked single-cycle Terahertz electromagnetic pulses and femtosecond magneto-optic probes, observing signals consistent with a uniform in-plane antiferromagnetic magnet driven by field-like Terahertz NSOTs with a torquence of 150-plus or minus 50 cm2a1s1. At incident Terahertz electric fields above 500 kVcm1, nonlinear dynamics with massive nil-vector deflections by as much as 30 degrees are observed, and the data agree well with a micromagnetic model, indicating that fully coherent nil-vector switching by 90 degrees within 1 PS is within close reach. This article was authored by Y Behavits, AL Chekhov, SU Bodner, and others.