Luxury home buyers in Santa Clara County last month caught a small break. After months of steadily increasing year-over-year sales and prices, the market for high-end homes — defined here as those selling for $3 million or more — plateaued in January.

The news came in a report from Coldwell Banker Residential Brokerage for the Silicon Valley Business Journal based on transactions recorded in the county by the Multiple Listing Service.

Nancy Robinson, the real estate firm’s regional vice…